# Compressor/Motor starter



## QMED (Sep 14, 2016)

I'm sure you already checked these but here goes.

Does motor draw nameplate current? I'm assuming it's the overload on the starter tripping? Sometimes there are high pressure switches that can trip the control circuit.

Hows's the compressor mechanically? Does it spin ok? Are bearings good on motor and comp?

What type of compressor? Is this a hermetic or semi hermetic ac compressor? Is the valve train working? How are the pressures?

I think there might me something obvious I can't think of which is not unusual haha


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## Ctsparky93 (Sep 17, 2016)

I would check rotation of the motor. Did you get the same starter and O,L?. If some one checked the motor make sure every thing is wired correctly in the pecker head. If that good then ohm out the motor and make sure nothing is locked up mechanically. 


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## MechanicalDVR (Dec 29, 2007)

Have you taken amp readings?

Could you have switched rotation?

Have you checked the motor yourself?

Clients lie and the last guy may have missed something, why didn't he leave it running?


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## John Valdes (May 17, 2007)

I would start with the motor connections. Make sure this motor is hooked up correctly.


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## frenchelectrican (Mar 15, 2007)

Hey Wrongun .,

How big this motor is what ya looking at ?

What size starter it is?

as other guys posted they are dead on the spot with basic troubleshooting on this.

If this is belt driven compressor you will have to check the alinement too.

There are few compressor unit they genrally will I will say again Will have a rotation marking on it so pay attetion to it. 

some of the compressor do have low oil cut off ( a float switch to prevent bearing damage if the crankcase oil get too low) if it did have it and see some case someone bypass it. 

Oh yes also check the supply voltage before ya turn the compressor on and when you manged to get it started check the voltage again to make sure.


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## MDShunk (Jan 7, 2007)

WronGun said:


> We replaced a Siemens magnetic starter today with the same exact unit that was previously blown.
> 
> Motor is a 3Phase 208 Wired in Low Voltage
> 
> ...


My car won't start. What could it be?

Not nearly enough information to even guess. What testing was done? Amp draws while starting? Even on all legs? Meg motor and conductors from starter to motor? Does the driven load spin freely? Unloader valve confirmed open? Wired per dataplate confirmed? All three phases present at motor when starter pulls in? 

Contacts get red hot or do you mean you can see the overload heaters start to glow? Correct overloads? Correct starter frame size? 

There's like a million things to simply "look" at, most take a minute or less to confirm. There's some testing that should be done, and most of those only take a couple minutes each.


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## John Valdes (May 17, 2007)

My bet is still on the connections. How many leads? HP?


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## Wirenuting (Sep 12, 2010)

Air compressor?
Check the unloading valve
Check to see if a valve dropped


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## Scat (Aug 30, 2017)

My 1st thought is that you are missing a phase.

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## John Valdes (May 17, 2007)

WronGun said:


> We replaced a Siemens magnetic starter today with the same exact unit that was previously blown.
> 
> Motor is a 3Phase 208 Wired in Low Voltage
> 
> ...


Well, what are the results?


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## Cow (Jan 16, 2008)

It's too bad you don't have someone with motor controls experience to mentor you Wrongun. Just thinking out loud here.

Once you get the hang of all the basic checks and have the proper meters to do so, motors and controls are fairly straightforward. A little tough to explain over the internet, if you had someone there with motor control experience you could watch do it, you'd pick up a ton of this stuff just in the half an hour or so it'd take them to troubleshoot it.


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## WronGun (Oct 18, 2013)

We replaced just the guts of this Siemens magnetic starter which wasn’t letting power pass through. Same unit that’s been there for years 

Now we are getting power at the motor but we still have this issue. 

I’m going to check a few more things before I tell him he needs the motor serviced. 

The switch acts like it’s getting heavily overloaded before tripping. 


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## Wirenuting (Sep 12, 2010)

Is it an air compressor?
Is it an alternating dual unit?
Is it a 2 stage compressor?
Is the unloading valve stuck?

The unloading valve releases the air off the compressor head so she can stroke and get going. If the unit stopped on an upstroke and didn’t unload she may just sit there and fight to over come the pressure.


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## Wirenuting (Sep 12, 2010)

WronGun said:


> We replaced just the guys of this Siemens magnetic starter which wasn’t letting power pass through.
> 
> Now we are getting power at the motor but we still have this issue.
> 
> ...




E38 overloads? 
https://w3.usa.siemens.com/powerdis...t-catalog/Documents/SF-11-Sect-17-122-133.pdf


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## frenchelectrican (Mar 15, 2007)

Wirenuting just hit the bulleye !! 

I was supecting it was wrong heater size.

I have a chart in my office and it say same thing too low a heater size with that size of motor.

change the heater then it will work properly.

Note: I look up it should be *E67* but after you install the correct heaters double check the running amps to make sure it hair below the heater rating unless the SF kick in play.


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## Bird dog (Oct 27, 2015)

frenchelectrican said:


> Wirenuting just hit the bulleye !!
> 
> I was supecting it was wrong heater size.
> 
> ...


Bottom of the nameplate, it looks like it says 40 degrees C Ambient.

23amps x 1.25=28.75amps


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## Cow (Jan 16, 2008)

I'd be using E65 if the ambient temp was the same between the starter and a 1.15 SF motor.


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## WronGun (Oct 18, 2013)

UPDATE:

Last time we went to service this compressor we changed the burnt out magnetic relay switch and the heater overloads. 

We tested line side , load side , and phase rotation. 

Turned on the compressor , filled the tank up to 200psi and verified it would turn off by itself 

(This thing is old)

I’ve been told the motor was serviced right before we did our part. 

I get a call saying it won’t turn on. I go yesterday to check it out and the new Siemens starter is toast again. 

Just wondering did I miss something here? I believe I initially did the right check points, is it safe to say the motor may be bad ?











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## gpop (May 14, 2018)

WronGun said:


> UPDATE:
> 
> Last time we went to service this compressor we changed the burnt out magnetic relay switch and the heater overloads.
> 
> ...



looks like a 2 stage compressor. 200 psi sounds like a high setting have you checked the max pressure of the tank to confirm that 200psi is allowed.

on the pressure switch there should be a small airline called a unload line. It goes to a valve that is mounted in the pressure switch. When the compressor turns off the lever that holds the contracts in the pressure switch should hit the valve and you should hear a loud hiss of air as it vents the piston to check valve on the compressor. As the valve doesn't come included with the pressure switch its possible that someone changed it and plugged the line.

We really need to know what a meter reads. Voltage, amps starting and running. Also check the pecker head wiring and see how its connected its not a hard lift. It really takes something special to burnt up a contactor so something doesn't sound right.


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## WronGun (Oct 18, 2013)

The unload line is covered in oil and just dangling , not even connected.

This is something I brought up to Owner. I explained I can check and install the electrical portions but I do not work on compressors...

I mentioned the unload line to him he told me well it’s been like this and working for 10 years. ?! 



The psi was actually under 200 before it shut-off. 


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## gpop (May 14, 2018)

i dont use siemens very often so where is the contact coil voltage marked?


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## gpop (May 14, 2018)

WronGun said:


> The unload line is covered in oil and just dangling , not even connected.
> 
> This is something I brought up to Owner. I explained I can check and install the electrical portions but I do not work on compressors...
> 
> ...


Tell him that $25 dollar valve is getting expensive. (its not electrical its just a valve mounted in the pressure switch)

The drive belts have probably been loose for years and someone tightened them so now the motor can not get started with out the unload valve.


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## paulengr (Oct 8, 2017)

Plus did you check contactor sizing? Overloads? Amps? Breaker? Parts changing without identifying root cause gets expensive quickly.


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## gpop (May 14, 2018)

Quick search on a iron man has the max psi rating at 175 psi. Kinda brave to go any higher especially on a old compressor. Next call might be that the motor is laying in the car park.

As a industrial electrician you learn that we have a responsibility to understand the machines we are working on. If a electrical switch allows for a compressor to overload its tank then there first question is who set the switch.


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## WronGun (Oct 18, 2013)

I replaced the starter with the identical Siemens model that he has been using for years. 

Very simple. Nothing to really screw up on my end. 


I was very up front with him through the process, even suggested someone who works on motors and is familiar with the compressor to look at it. 

I dont understand I didn’t think these were that expensive. Everyone in this industrial building has compressors that look 90 yrs old ?!

At this point and age why not invest in something new? 






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## WronGun (Oct 18, 2013)

frenchelectrican said:


> Wirenuting just hit the bulleye !!
> 
> I was supecting it was wrong heater size.
> 
> ...




E67 is the exact heater size, I installed into this starter 


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## paulengr (Oct 8, 2017)

WronGun said:


> I replaced the starter with the identical Siemens model that he has been using for years.
> 
> Very simple. Nothing to really screw up on my end.
> 
> ...




Without an unloading relay and if the pressure relief valve isn’t working (typical at this age) it’s a bomb. It will eventually kill somebody especially if it’s clearly overloading so who knows if the gauge is right either or pressure could be even higher.



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## WronGun (Oct 18, 2013)

paulengr said:


> Without an unloading relay and if the pressure relief valve isn’t working (typical at this age) it’s a bomb. It will eventually kill somebody especially if it’s clearly overloading so who knows if the gauge is right either or pressure could be even higher.
> 
> 
> 
> Sent from my iPhone using Tapatalk




Ok, but would this cause another starter to blow ? 


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## 460 Delta (May 9, 2018)

You need to check the input voltage before starting, and as it's running. If it is a line voltage coil, the voltage may drop too low causing chatter, especially if it's a 230vac coil. Also check the oil level sensor and pressure switch, these can and will cause contactor chatter that is lethal to starters. Pressure switches are a item a I carry and replace often.
Iv'e made many a service call that a pint of oil in the compressor fixed the "starter is making a heck of a noise".


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## WronGun (Oct 18, 2013)

460 Delta said:


> You need to check the input voltage before starting, and as it's running. If it is a line voltage coil, the voltage may drop too low causing chatter, especially if it's a 230vac coil. Also check the oil level sensor and pressure switch, these can and will cause contactor chatter that is lethal to starters. Pressure switches are a item a I carry and replace often.
> Iv'e made many a service call that a pint of oil in the compressor fixed the "starter is making a heck of a noise".





Voltage was 208V across all lines, didn’t check while it was running 


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## 460 Delta (May 9, 2018)

WronGun said:


> Voltage was 208V across all lines, didn’t check while it was running
> 
> 
> Sent from my iPhone using Tapatalk


 Is the coil a 208 vac or a 120 vac and using the neutral?


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## WronGun (Oct 18, 2013)

460 Delta said:


> Is the coil a 208 vac or a 120 vac and using the neutral?















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## 460 Delta (May 9, 2018)

The pic is a little low and I can't see the coil voltage, but a quick p/n search says it's a 240/120 coil, you'll need to use the neutral to use that coil, 208 is gonna be a little low for a 240 vac coil, especially if there is some voltage drop at max pressure right before shut off.


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## micromind (Aug 11, 2007)

My vote is for either a bad pressure switch or a bad low oil level switch that causes the starter to chatter thus burning up the contacts.


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## WronGun (Oct 18, 2013)

I will have to look at other things on this compressor. 

The starter & Wiring haven’t been changed and have been running this compressor for at least 10–15 yrs. I would rule out the starter/coil type or line voltage/Neutral that was mentioned. 


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## gpop (May 14, 2018)

WronGun said:


> I will have to look at other things on this compressor.
> 
> The starter & Wiring haven’t been changed and have been running this compressor for at least 10–15 yrs. I would rule out the starter/coil type or line voltage/Neutral that was mentioned.
> 
> ...



Quick lesson on motors. 

When a motor starts it pulls rotor lock amps (rla) which is roughly 7 times full load amps (fla). This means if the motor runs at 23 amps rla will be around 161A. (once the motor starts to turn the ampage will drop until it reaches full speed at which point it should be less than fla)

If you pull 161A on a 10g wire you will get voltage drop. The coil voltage required for your contactor is 220v. You are using 208v so add a 30v drop and now you are down to point where the coil will start to open and close. We call that rattling. 

If the motor can get up to speed while the contractor rattles then the amps will drop so the voltage will climb so the coil will stay closed. 

With no unloading valve you maybe in that rattle stage for 20 seconds and that can be enough to burn the coil out. The first start you did was easy as there was no pressure to start with. (your overloads are rated for 20 seconds so dont expect the overloads to kick in until its rattle for a while) 

This is simplified but it should give you the basic idea.

The fact it has worked for years really doesn't matter and if you get hooked on that idea then there's not much we can do to help you.


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## varmit (Apr 19, 2009)

Oh the famous "It has always worked before". 200 PSI is way too much pressure for this type of compressor: The compressor will get so hot that it is damaging the cylinders. If the relief valve is not working, you are starting at near locked rotor current on each start cycle. 

As someone else mentioned, if the belts have been tightened or replaced, this can change the load dramatically. This can also affect the mechanical load on worn bearings.

Meg the motor. If has been abused like this, the winding insulation may be failing. 

The compressor needs to be repaired or replaced, otherwise you are wasting you effort. The existing compressor probably has too high of an air volume demand, so someone has set the compressor to run at a higher pressure to increase draw down time rather than install a larger compressor. Adding receiver volume is a better patch for this. Fixing air leaks can make a huge difference in compressor demand also.


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## splatz (May 23, 2015)

WronGun said:


> I do not work on compressors...


I have some bad news for you. If I am reading this thread right you appear to be working on a compressor. :laughing: 

@WronGun, you're getting some excellent help with the work here, it's an excellent thread. I certainly couldn't add anything to the specifics. I could reiterate that you might make fewer assumptions: 

* Don't assume that today's Siemens starter is the same as 2008's or 1998's Siemens starter of the same number. Related: don't assume the overloads were ever correct just because it functioned. 

* Don't assume the last guy did things right. Related: Don't assume you'll get away with whatever he got away with. 

* Don't assume the customer actually tested what they said they tested. 

* Don't assume you got the rotation right; check your work with the proper tool. Related: check the current and voltage in different states even if you're not sure what your results will indicate. 

But of all the good advice I think @Cow's has the best advice embedded: 



Cow said:


> It's too bad you don't have someone with motor controls experience to mentor you Wrongun. Just thinking out loud here.


With all due respect it sounds like you're over your head here. 

IMO this isn't a good one to learn by doing. An old compressor that clearly hasn't been properly maintained and possibly wasn't even installed right is an accident waiting to happen, possibly a very serious accident. Even if nobody gets hurt, someone's getting sued. You're going to be the last one that touched it. You'll wind up with a black eye. 

I'd bring in someone that knows how to service compressors, or I'd pass.


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## telsa (May 22, 2015)

Old systems draw out every manner of abuse... like the owner adding additional compressed air taps to the original system.

As for the owner being straight with you, don't count on it: 

1) general level of ignorance; 

2) no desire to pay up for fundamental re-work -- like a new compressor.

Their assumption is that you're a miracle worker, so why get into sticky technicalities?

At this level of air demand, the owner ought to have a post-compression cooler. You can go to YouTube for videos posted up from guys that have improvised their own. The benefits are many.

Next, we're in Summer. Local temperature has an impact. It can really flip the equation. A system that gets by in March can come to grief in July.


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## 460 Delta (May 9, 2018)

WronGun, the only thing that I assume out of the gate is that what I’m told is wrong and the guy before me connected it wrong. See my 

thread about ignoring my own troubleshooting advice. The original starter may have had the coil changed in the field to a 208 vac and that was that. I currently tend to 13 plants that all have at least two compressors in them so I have a little experience in dealing with compressors just like that one. 
Fun fact, I just got a call about a compressor down, I asked if they checked the oil level, umm no, well it’s probably low on oil, if that doesn’t fix it call me back, no call.


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## Going_Commando (Oct 1, 2011)

You are getting a lot of good advice here. First things first. 

1) Have you megged the motor?
2) When you replaced the starter did you verify rotation and check amperage readings on each phase? If you didn't verify rotation and let her run backwards, then you probably smoked the compressor pump since it doesn't get lubricated if it's going the wrong direction. 
3) Did you check the compressor oil level before you powered her back on?

These other guys are more knowledgeable than I when it comes to compressors (and a lot of other things), but those are the important things to check when messing with compressors. It's also important to check the pressure switch setting and make sure it is working correctly, and you are going to get a lot of heat if the compressor doesn't have an unloader valve and it has short cycle times.


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## Wirenuting (Sep 12, 2010)

This is your unloading valve?
It needs to be hooked up or when the compressor cycles it will try to start with the position head pressurized. 
This may not be a disaster right away if the unit cycles rarely. Old compressors will leak air past the rings and bleed it off. 
But when the unit starts Soon enough it will cause a starter to fry and do a slow cook of the motor. 

I would replace the starter if it’s fried and motor also. 
I would also look at the tanks pressure relief valve and see if it’s still there. With out it the unit is a cannon waiting for the chance to go. The tank will have a data plate listing the pressure, some people like to plug the relief just to gain a few pounds. 

Kind of like a water heater with no T&P valve.


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## Wirenuting (Sep 12, 2010)

An unloading valve as showing hooked to the pressure switch. 

A mechanical action,,, off motion, triggers the small valve and releases pressure on the compressor head..


Kill a motor and or starter with out one.


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## WronGun (Oct 18, 2013)

Wirenuting said:


> This is your unloading valve?
> 
> It needs to be hooked up or when the compressor cycles it will try to start with the position head pressurized.
> 
> ...




This was one of the first things I mentioned. 

Who normally works on the equipment? Is it part of our trade ?

I’ve only hooked up newer ones with no issue. Do they all require magnetic starters? this one was clearly marked. 


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## Wirenuting (Sep 12, 2010)

WronGun said:


> This was one of the first things I mentioned.
> 
> Who normally works on the equipment? Is it part of our trade ?
> 
> ...


We have a compressor guy here, he’s old and lazy. When things get broken I get sent by default because I’m old and not lazy.
A lot of his unloaders leak and get stuck open, but that’s his problem and they are easy to spot by the oil weeping out of them.. they Hissss all the time. 

All of ours here have starters, everything is 3 phase for us. 
Some of our units are big and have electric powered unloaders, but they are few and far between. Most have the type in the picture I had posted. 

This picture has my finger pointing towards the pressure relief valve. New and shiny.
Next to my finger are 2 cylinder head unloaders that are tied to the control panel. They pass to a solenoid that denergizes after each cycle. It is also tied to the oil sump to depressurization that. 

The little ones we use on sprinkler systems are single phase and don’t have starters. They don’t need the protection and rarely cycle,,, but they have unloaders on them also.


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## MDShunk (Jan 7, 2007)

WronGun said:


> Who normally works on the equipment? Is it part of our trade ?


Yes and no. Every electrician will bring power "to" a new or relocated air compressor.
Service electricians often get the call to work on little air compressors like you're working on if the issue seems electrical. 
Factory maintenance electricians usually get first crack at air compressors of every size.
For large compressors, or air compressors with seemingly all mechanical issues, a specialist air compressor service company is normally called in.


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## gpop (May 14, 2018)

One of my favorites 

The motor was sent out to be checked, they found no problem with it. Its been running like that for years.

What they really meant to say was.......Didn't know what was wrong so the big hairy mechanic removed the motor and beat the crap out of the pulley until it snapped in half trying to get it off. We found a pulley that was about the same size so it should be ok. 
The motor shop said it was good so big and hairy reinstalled the motor and stretched the belts till you could play E sharp then jammed the wires back together. There was only 3 wires so it has to be correct.


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## MDShunk (Jan 7, 2007)

gpop said:


> What they really meant to say was.......Didn't know what was wrong so the big hairy mechanic removed the motor and beat the crap out of the pulley until it snapped in half trying to get it off. We found a pulley that was about the same size so it should be ok.
> The motor shop said it was good so big and hairy reinstalled the motor and stretched the belts till you could play E sharp then jammed the wires back together. There was only 3 wires so it has to be correct.


That's destined to become a classic. Love it.


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## Flyingsod (Jul 11, 2013)

MechanicalDVR said:


> Clients lie and the last guy may have missed something, why didn't he leave it running?



This always applies to everything everywhere at any time. Well said Mech




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## Flyingsod (Jul 11, 2013)

460 Delta said:


> You need to check the input voltage before starting, and as it's running. If it is a line voltage coil, the voltage may drop too low causing chatter, especially if it's a 230vac coil. Also check the oil level sensor and pressure switch, these can and will cause contactor chatter that is lethal to starters. Pressure switches are a item a I carry and replace often.
> Iv'e made many a service call that a pint of oil in the compressor fixed the "starter is making a heck of a noise".




Thanks. I was scratching my head wondering how a motor could kill a starter. You explained it well noting it’s prolly not the motor... which is what I was thinking but I couldn’t think of an alternative. 


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## Flyingsod (Jul 11, 2013)

WronGun, am I reading right that there are now two dead starters or is it just the original that failed? Also much more info needed about the failure(s). What exactly was wrong? That will tell us where to look next. Saying it burnt up just doesn’t give enough info. Also I didn’t notice where you said you did an amp check. That’s another crucial piece of info. 


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## gpop (May 14, 2018)

Just as a foot note. Most starters can be field stripped and the coil replaced (especially useful if you have the wrong coil to start with). If the contacts are not burnt out or welded then its a cheaper option then replacing the complete starter.


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## gnuuser (Jan 13, 2013)

gpop said:


> Just as a foot note. Most starters can be field stripped and the coil replaced (especially useful if you have the wrong coil to start with). If the contacts are not burnt out or welded then its a cheaper option then replacing the complete starter.


true they can be rebuilt if you have the parts and time to do it. but for the most part replacing them is the fastest option for production equipment in order to keep the yapping dogs off your backside.

if the starter is rebuild-able we like to use them for training apprentices,
they are great tools for them to learn about.

what happens when a starter chatters is sustained arc on separation between contacts 
every time a contact separates under load there will be an arc for a short duration and this burns and partially melts the surface of the contact.
as long as the contact is not chattering the damage is negligent.
but if it is chattering the contacts do not have time to cool down.
if it happens too often the contacts can weld together.
this same condition can happen with breakers and switches as well


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## frenchelectrican (Mar 15, 2007)

gnuuser said:


> true they can be rebuilt if you have the parts and time to do it. but for the most part replacing them is the fastest option for production equipment in order to keep the yapping dogs off your backside.
> 
> if the starter is rebuild-able we like to use them for training apprentices,
> they are great tools for them to learn about.
> ...



This what I get from time to time when the concants chatters pretty hard and do make serious arc pitting marking on the concants buttons espcally if ya dealing with 400 and up voltage system which I get it from time to time.

I just got done a service call.,, a 30 gallon compressor went bad because of low oil cutoff keep burning up starter up. and just a liter of fresh oil do the trick .,, jezz some peoples do not have brains just blank as coconut shell !!!


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## frenchelectrican (Mar 15, 2007)

I just want to add to my last part of my comment.,

Just be aware the low oil cutoff switch will not show up when it start up cold or not running for more than 15 minuites but once it start running and when the low oil cutoff do kick in it will cycle pretty often depending on how low the crankcase oil get. and just watch out with some idiots due some of them will bypass it. ( the one they did bypass it will fry up the compressor unit once the oil get super low or ran out of oil )


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## WronGun (Oct 18, 2013)

This was all helpful and good to know. I mentioned A lot of points to him but tried to emphasize him buying a new compressor. 

I’m back at the complex tomorrow installing his neighbors new compressor 


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## JRaef (Mar 23, 2009)

gpop said:


> i dont use siemens very often so where is the contact coil voltage marked?


 The asterisk in the part number on the starter label is where you insert the coil voltage that you want, but they don't put that on the label of the starter itself. The default is a dual-voltage 120/240V coil.











WronGun said:


> Voltage was 208V across all lines, didn’t check while it was running
> 
> 
> Sent from my iPhone using Tapatalk





460 Delta said:


> Is the coil a 208 vac or a 120 vac and using the neutral?


I see no evidence of there being a neutral run out to that starter box.




460 Delta said:


> The pic is a little low and I can't see the coil voltage, but a quick p/n search says it's a 240/120 coil, you'll need to use the neutral to use that coil, 208 is gonna be a little low for a 240 vac coil, especially if there is some voltage drop at max pressure right before shut off.


If in fact it has the default dual voltage coil, I know for a fact that 208V would have been tolerable 20+ years ago when it was Furnas, but Siemens made some changes when they moved the production line to Mexico. If you give only 208V to a 240V coil now, it over heats, swells up the coil frame and can jam the contactor armature yoke. So when you go to start it next time, either the armature doesn't pull in all the way and the contacts arc until fried, or the armature gets stuck in and can't turn off.


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## 460 Delta (May 9, 2018)

Yep JRaef, that’s what I’m saying, and that’s if it is at 208vac at all under load. I wouldn’t be surprised if it’s 200 or less at start and max load right before shutdown. In my experience, a 208 Star needs extra care to compensate for voltage drop, on dual voltage motors it’s always close to the bottom as is. 
Siemens has dynamited some good lines in my opinion, ITE is the other one that comes to mind.


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## Flyingsod (Jul 11, 2013)

frenchelectrican said:


> .,, jezz some peoples do not have brains just blank as coconut shell !!!



Nice. I thought you were going to say some people don’t have brains, just blank checks. Which is a comforting thought to us service techs. [emoji3]



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## 460 Delta (May 9, 2018)

At least your compressor is pretty clean, mine are generally covered in sand, gravel, cement, ash, or some admixture or any and all of the above. I’ve had to dig like a ground hog in a few old plants to get to the valve to isolate it out!


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## JRaef (Mar 23, 2009)

460 Delta said:


> At least your compressor is pretty clean, mine are generally covered in sand, gravel, cement, ash, or some admixture or any and all of the above. I’ve had to dig like a ground hog in a few old plants to get to the valve to isolate it out!


Compressors in sawmills... oil and sawdust. A fire just waiting for a Murphy’s Law moment. A really common thing is that when originally installed, they had air cleaners on the intakes. But over time someone forgets to change them and in order to get running, they just remove them and start sucking sawdust into the compressor. They will then repeatedly rebuild the cylinders and change the oil more than they should, but eventually the unloaded valve gets so clogged up that it gets stuck closed or open. Then either way, it somehow becomes an “electrical problem” with the starter, breaker, fuses, whatever. When I would point out the real cause, everyone denies knowing who took the air cleaner off...


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## frenchelectrican (Mar 15, 2007)

JRaef said:


> Compressors in sawmills... oil and sawdust. A fire just waiting for a Murphy’s Law moment. A really common thing is that when originally installed, they had air cleaners on the intakes. But over time someone forgets to change them and in order to get running, they just remove them and start sucking sawdust into the compressor. They will then repeatedly rebuild the cylinders and change the oil more than they should, but eventually the unloaded valve gets so clogged up that it gets stuck closed or open. Then either way, it somehow becomes an “electrical problem” with the starter, breaker, fuses, whatever. When I would point out the real cause, everyone denies knowing who took the air cleaner off...


Oil and sawdust that useally can be a major headache espcally with two stages units.,, 

I have one few years back it run even the starter is off after a hard running and it took me just a second to figure it out., basically simauir to diesel engine once you get sawdust and oil inside the piston hot enough it will run by itself and the compressor motor can become generator ( it did happened to one customer just once but after that never see it again)


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