# Abb acs150



## kthack0441 (Sep 6, 2018)

I've recently had a drive be utterly destroyed by a forklift due to poor placement from the machine manufacturer. Upon replacing, my company opted for an ACS150 rather than the PowerFlex that I'd typically use in this situation. I'm having difficulty because of this. This is simply a 3 wire in, 3 wire out connection with no other inputs at all. All I need is for the drive to initiate output when power is applied rather than having to open the enclosure to hit start. I've tried adding a selector switch to give a constant on input, but I've had no luck. 

I'm not too familiar with this particular drive, is there an easy way to accomplish this?


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## MDShunk (Jan 7, 2007)

Curious... what is the application? Sounds like you make and break the line side for stop/start, and have unattended restart? That's a little odd.


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## kthack0441 (Sep 6, 2018)

This is simply to power a motor for a small section of conveyor at a set speed. Personally, I'd prefer to just install a gearbox and go without a drive, but the company wants to keep things in line with manufacturer standards. It seems a bit asinine, which is why I've been pulling my hair out trying to figure it out.


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## John Valdes (May 17, 2007)

I would not EVER want a drive to use its power source as its start command.
A drive needs time to power up.
You need to use a start/stop input at minimum.
Its simple enough to do and what you are asking to do is flat wrong.


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## John Valdes (May 17, 2007)

Please see the following link.

https://www.electriciantalk.com/f3/attention-new-members-required-profile-fields-258186/


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## gpop (May 14, 2018)

In the manual you will find something in the program that can disable the safety so the drive starts on power up. It next to a lot of warnings about unintended starting.


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## gpop (May 14, 2018)

Oh.forgot drive also needs to be in auto


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## gpop (May 14, 2018)

If you use a standard macro and added a switch between Auxiliary voltage output: +24 V DC, max. 200 mA (24+) and Digital input one (D1) then added a jumper between Auxiliary voltage output common (gnd) to Digital input common (com) by simply turning the switch on will start the drive and turning it off will stop the drive.

Drive will not start unless the input signal on D1 is seen as off after power up (e.g you have to turn the switch off then back on for it to start)

Now you can go 3 wire and jump both of the start and stop inputs and the drive should start as soon as it powers up but its a bad idea.


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## John Valdes (May 17, 2007)

gpop said:


> In the manual you will find something in the program that can disable the safety so the drive starts on power up. It next to a lot of warnings about unintended starting.


I had no idea. Thanks. 
But is it really a good idea? Or is it a built in function I have never seen or heard of?


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## frenchelectrican (Mar 15, 2007)

gpop said:


> If you use a standard macro and added a switch between Auxiliary voltage output: +24 V DC, max. 200 mA (24+) and Digital input one (D1) then added a jumper between Auxiliary voltage output common (gnd) to Digital input common (com) by simply turning the switch on will start the drive and turning it off will stop the drive.
> 
> Drive will not start unless the input signal on D1 is seen as off after power up (e.g you have to turn the switch off then back on for it to start)
> 
> Now you can go 3 wire and jump both of the start and stop inputs and the drive should start as soon as it powers up but its a bad idea.


I heard about it and one guy told me about some on that and we both agree it was not the best at all due safety issue.

I just dont understand how hard to get a remote start stop buttion station and do it right .,,

OP .,
It would be easier to just add a pushstart station or a relay to the vsd unit ?


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## gpop (May 14, 2018)

John Valdes said:


> I had no idea. Thanks.
> But is it really a good idea? Or is it a built in function I have never seen or heard of?


I guess from the warnings in the manual that some people in the past have hooked a drive to the line side of a starter. Effectively using the starter to cut power to the drive thus stopping it. There is a warning in the manual that this should not be installed this way and the drive is rated for 15000 power up of capacitor bank cycles. 

Now for testing different speeds i can see being able to install on the line side of a starter as useful (e-stop would still work, quick and dirty install, Its a small motor and drive), but this is being described as a fully installed drive so its either a project that never got finished or some one ignoring the manufacturers instructions.


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## MDShunk (Jan 7, 2007)

John Valdes said:


> I had no idea. Thanks.
> But is it really a good idea? Or is it a built in function I have never seen or heard of?


Before the "safe off relay" was a function internal to the drive that broke the DC bus, it was somewhat typical to use a safety rated contactor to kill line side power when the estop was pressed or guard doors were opened. Upon reset of the estop circuit, line side power is reapplied. In that case, however, a controlled restart sequence is initiated by way of a remote start signal. In the case on the OP's uncontrolled restart.... well, I'd like to see the OSHA required 5 second warning horn/bell for audible warning of an automatic unattended restart, at least. What he has exists, though, and they've no doubt coped with it somehow. For all we know, this could be 1 drive out of 100 that are similarly arranged in his facility.


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## frenchelectrican (Mar 15, 2007)

kthack0441 said:


> This is simply to power a motor for a small section of conveyor at a set speed. Personally, I'd prefer to just install a gearbox and go without a drive, but the company wants to keep things in line with manufacturer standards. It seems a bit asinine, which is why I've been pulling my hair out trying to figure it out.


To OP .,

I am thinking it is not super hard to relocated the VSD unit to different location and with conveyor you should set that up to start up before or after the main item is start up so it very simple is put a relay along the main item like a main grinding motor or discharge chute or whatever it is.

get the start and stop command signal from the main motor if you want it start up corranted ( in sequence ) 

just like everyone else here comment on safety of unattented start up on conveyor.

check with the manufacter of that machine to see if they allowed modification and I am sure they will do it.


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## John Valdes (May 17, 2007)

I did not even consider safety.
I was considering proper operating practice. I still know of no drive manufacturer that would recommend and switching ahead of the drive. Contactors were always a no no.

I have seen some ABB DC drives that had the contactor on the line side and I was certain it was for Emergency stop. A curiosity for sure.

Has the control world moved past this thinking? I have been out of this business for a very good while.
But it seems even today it would be a bad idea to put a contactor on the line side of a drive. I mean what about braking? Motor will coast after a complete power loss. This alone would make it unsafe. 
I had one very large motor on a balancing system that was still coasting when I arrived. I got the call the day before. Turbine balance machine on a rail flatbed.
Also all the drives I have ever used, needed a moment or two to power up. Is this not the case anymore and how and why? Thanks


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## paulengr (Oct 8, 2017)

The "safety" feature is to prevent unintended surprise startups. It defaults to "on" in most drives so that if the start/run input is powered up when the drive first boots, it ignores it or throws a fault code. There is always a parameter to disable it.

But there's a more important mistake here. On power up the drive has to precharge the capacitors before it switches to run. In and of itself that's not bad except one thing...the precharge circuits are NOT designed to be frequently started and stopped. In almost all drives they are a little undersized so if you switch power on and off to a drive several times in a row, you will burn the precharge circuit up. That is exactly why in the manual for both the ABB ACS and in the AB Powerflex manuals, it specifically tells you to NOT do this. I see it done quite often on conversions from starters to drives and see many premature drive failures because of it. Depending on the size of the transformer feeding it and the drive design, it may survive it, and paradoxically usually the larger the drive, the more likely it is to burn up from this, but the general practice is never to do this. If you insist on using a contact, bypass it so the drive is always powered up from the disconnect/circuit breaker and then use the contacts in the starter to close in the run command on the drive.


And I don't really care what the OEM did. What they did was wrong, pure and simple. In fact conversions from (improperly wired) Bulletin 1336 installs to Powerflex specifically fell victim to this sort of screw up. The old 1336 drives would survive it but not the Powerflexes. They'll work OK for a few months but no way you're getting 10+ years of life out of one if you do this.


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## MDShunk (Jan 7, 2007)

There's an AB knowledgebase article about automatic restart of powerflex drives that says to use a TDR on the run/enable circuit set to twice the amount of time it takes the drive to reach the ready state upon powerup. In the case of machine estops that kill drive power, the PLC is used for that purpose.


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## gpop (May 14, 2018)

John Valdes said:


> I did not even consider safety.
> I was considering proper operating practice. I still know of no drive manufacturer that would recommend and switching ahead of the drive. Contactors were always a no no.
> 
> I have seen some ABB DC drives that had the contactor on the line side and I was certain it was for Emergency stop. A curiosity for sure.
> ...


Braking a load is normally for convenience rather than for safety. My main concern would be for the drive to be programmed for a flystart. 

If the poco has a short power cut once the power is restored the drive may try to ramp the load from zero even if its spinning. This can have a affect of a very aggressive braking system.

At least with flystart programmed the drive can be restarted then after a few seconds once its caught hold of the load and starts to increase speed you can use the stop controls and it will use the braking program. 

Most drives have a enable circuit that i presume disconnects the dc buss thus you have a hard wired safety. E-stops are meant to be hard wired fail safe so we run the enable circuit via a e-stop relay. If a drive manual does not give a e-stop option then adding a starter may be the only option.


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## John Valdes (May 17, 2007)

I thought the "Flying Start" was to over come things like fans that could be spinning in the opposite direction when the drive is started.
This can happen when an exhaust fan for example is getting airflow from outside. Subsequently trying to start the load with inertia in the opposite direction of the drive programmed direction.

Is there concern if the motor is moving in the correct direction on start up?
Other than regen current I don't see an issue.

Thanks


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## MDShunk (Jan 7, 2007)

gpop said:


> Most drives have a enable circuit that i presume disconnects the dc buss thus you have a hard wired safety.


Actually, it doesn't, which is why many OEM's (prior to drive integrated safe off features that do break the DC bus) chose to dump power to the whole drive.


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## MDShunk (Jan 7, 2007)

John Valdes said:


> I thought the "Flying Start" was to over come things like fans that could be spinning in the opposite direction when the drive is started.
> This can happen when an exhaust fan for example is getting airflow from outside. Subsequently trying to start the load with inertia in the opposite direction of the drive programmed direction.
> 
> Is there concern if the motor is moving in the correct direction on start up?
> ...


 Flying restart is also supposed to be used to restart things that may still be spooling down. It syncs the ac output of the drive to match the ac regen coming from the still spinning motor, sort of the same idea as bringing another generator online at a powerhouse.


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## paulengr (Oct 8, 2017)

A few very large drives have input and output contactors as do drives with a 3 contactor bypass system. The output contactor should make sense to most people since technically you're "backfeeding" the drive through the inverter side. Cheap bypasses use a 2 contactor style system. The extra front side contactor is in case the front end of the drive has shorted out. Without it if the drive fails, the bypass contactor does you no good until you go in and manually disconnect the drive wiring or pull the fuses. On large drives the contactor serves a similar purpose as well as often offering a grounding feature for working on the drive or the motor. BUT, BUT, BUT in either case the drive either has feedback from the bypass contactors, or controls the sequencing itself. And it has enables and other things to prevent problems. There is often some kind of anti-pump timer to prevent rapid cycling of the input contactor especially when one gets used. So never say never when it comes to input contactors but this is only for special designs that specifically incorporate this as a feature. Usually the drive or bypass contactor leaves the input contactor closed in unless there is a specific reason to open it, and then it opens it and leaves it open as long as possible.

"Safe off" is usually SIL 2. It usually does something like disconnect the logic signal to the firing logic and disconnect power to the firing circuit outputs. Standard hard wired enables are logic-only protection so they are SIL 1.

Flying start is for something entirely different. If the motor is already turning at a higher RPM than the rotating field that the drive puts out or it's running in the opposite direction, effectively the drive plugs the motor. The important point is that the rotating field created by the drive is slower than the motor, not whether or not it's in the opposite direction. The extremely high current is basically stall current but since the motor is attempting to break, it becomes a generator but at usually around 6X FLA. Very, very few drive front ends are capable of absorbing this much current and even a brake chopper may not be enough. Flying start algorithms start at maximum frequency with a low voltage and attempt to flux up the motor. Because the motor is turning slower, it doesn't draw much current but still attempts to turn with what little voltage the drive is putting out. The current will slowly decrease and go through a zero as the drive synchronizes to the motor. Then it suddenly increases again (drive is trying to plug/stall the motor) as the frequency gets too low. That's the signal for the drive and it restarts at the current (flying) speed.

Flying start is not without it's own problems. It doesn't always work text book perfect and often takes some fiddling to get it to work especially on very large motors. The big issue is if the drive can reliably detect the change in flux. Sometimes you can catch a motor, sometimes you can't once you are in the >500 HP realm. It is usually very easy to do with small motors.


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