# Hold for 3 min to start



## Handasee (Dec 18, 2009)

Customer has a Cutler-Hammer TRU-125-N1 Soft Start on a dust collector. 
To Start the motor (100HP, 600V 3PH) he has to hold the start button for 3 minutes before the motor begins to start. Simple 3 wire control. Checked all voltages going to soft start, all within limits. 
My guess is a capacitor on the control board (CA392-3). No electronic schematics available. Does not sound like a problem with the SCR's. Has anyone come across a problem like this before?
Customer cannot remove the dust collector from service at this time.
Only had an hour to look at it before they said run it.


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## Wirenuting (Sep 12, 2010)

Ramp up is 30 sec so I would almost think that it see's a jam. 
"Off the shelf solutions" normally stink

http://downloads.eatoncanada.ca/dow... Open/Installation Manuals/TRU-DCI Manual.pdf


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## Handasee (Dec 18, 2009)

Wirenuting said:


> Ramp up is 30 sec so I would almost think that it see's a jam.
> "Off the shelf solutions" normally stink
> 
> http://downloads.eatoncanada.ca/dow... Open/Installation Manuals/TRU-DCI Manual.pdf


Motor does not even start to ramp up until after approximately 3 minutes.
Mechanic checked all parts, he did not find a problem.
Forgot to add in original post that this is only happening during the first starting in the morning. No problem starting at coffee breaks or lunch breaks.


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## John Valdes (May 17, 2007)

Sounds like a programming error to me.


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## Handasee (Dec 18, 2009)

No programming on this unit.
Only adjustments are by potentiometers, 1)Rate (time of current ramping 2-30sec) and 2)Step (Starting Current/Torque)


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## JRaef (Mar 23, 2009)

I think your theory on the power supply has merit, it's a Switch Mode Power Supply that puts out 15VDC and if there is a problem with the SMPS being able to get it to voltage, it could be that. But in general, an SMPS either works or it doesn't, so even if it is doing this now, it's only going to get worse and fail in short order. 

I doubt the PCB schematic will be of much use, you would likely waste a lot more time trying to repair it than just the 10 minutes it would take to replace it. That starter is the Opal SS6 starter made by SAF Drives in Ontario, Canada, you could just give them a call and get a replacement board rather than waiting for your C-H distributor to call C-H, who will just call SAF and go through a lot of hands and ears to get what you need.

http://www.opalstarters.com/sites/default/files/M_OPAL_SS6_2.pdf


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## Wirenuting (Sep 12, 2010)

Handasee said:


> Motor does not even start to ramp up until after approximately 3 minutes.
> Mechanic checked all parts, he did not find a problem.
> Forgot to add in original post that this is only happening during the first starting in the morning. No problem starting at coffee breaks or lunch breaks.


They don't completely power the drive down at night do they?
If so it could very well be a bad board. 


Is there an exhaust damper on the collection system or a make up air damper? If so their might be a limit switch inside the actuator and its driving slow due to dirt build up. 
It could take hours to close at night. ie: drive open, spring return. 
If they are pneumatic they might open slow due to leakage but close quickly. This would allow problem to show up after break and lunch. 

Some of my dampers are a PITA because they take so long.

edit: since its so big a unit, I would really think there is a safety or interlock in line that's holding the world up. Better slow and safe then quickly sorry.


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## gnuuser (Jan 13, 2013)

i may be wrong in this but it sounds like a thermal issue with the pot or relay 
as you stated there is no problem after the unit has been running
only cold start
or possibly in the start switch itself ( had this once on a gaging machine)


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## Wirenuting (Sep 12, 2010)

gnuuser said:


> i may be wrong in this but it sounds like a thermal issue with the pot or relay
> as you stated there is no problem after the unit has been running
> only cold start
> or possibly in the start switch itself ( had this once on a gaging machine)


Some of my old SquareD (1960 era) maintained push buttons had to be held for about 20 seconds. They wouldn't latch and start the motors. They had a mechanical rocker built into them and were connected to the stop button.


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## Handasee (Dec 18, 2009)

JRaef said:


> That starter is the Opal SS6 starter made by SAF Drives in Ontario, Canada, you could just give them a call and get a replacement board rather than waiting for your C-H distributor to call C-H, who will just call SAF and go through a lot of hands and ears to get what you need.


Thanks JRaef. You know your drives. Just wish that there was a list of drives that are interchangeable.


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## Handasee (Dec 18, 2009)

Thanks everyone for your ideas.
I just purchased a new board from Saf.

Wirenuting- I've checked wiring all the way back to the board. Control voltage is there as soon as I push the start button, so it's not a damper switch etc. And by the way, since when is "1960 era" old! 

gnuuser- it could be a thermal issue. There is a capacitor that appears to be in parallel with whats labelled the "run relay". Untill I replace the board, I can't check out these ideas. Customer has to be running and replacing the board is the quickest way.


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## Wirenuting (Sep 12, 2010)

Handasee said:


> Wirenuting- I've checked wiring all the way back to the board. Control voltage is there as soon as I push the start button, so it's not a damper switch etc. And by the way, since when is "1960 era" old!


Well old is a relative term. When the buttons were installed there I was a twinkle in my fathers eye. 
When they were torn out and replaced, I was the old grumpy guy in a shop of new kids.


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## wdemos (Nov 27, 2008)

Interesting problem, but I am just as curious about who had the patients to find out it would start after holding the start button for 3 minutes.


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## Handasee (Dec 18, 2009)

wdemos said:


> Interesting problem, but I am just as curious about who had the patients to find out it would start after holding the start button for 3 minutes.


I don't know who had their finger on the start button, but when I did it, I pulled out all my arc flash ppe.


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## JRaef (Mar 23, 2009)

Handasee said:


> Thanks JRaef. You know your drives. Just wish that there was a list of drives that are interchangeable.


Most people who brand-label someone else's product are reluctant to let anyone know that, it makes them look bad, we tend to look at companies that innovate and develop products as more competent than those who just market them. But the harsh reality is that we also like "one stop shopping" for products, which is difficult for the bigger companies that then have to provide every kind of product we want. So the path of least resistance (from the bean counters) is to private label something that already exists from a smaller company or even a competitor. There is a lot more of that going on than most people realize.



Handasee said:


> Thanks everyone for your ideas.
> I just purchased a new board from Saf.


When you replace it, you can fiddle with the old board to see if you can diagnose it, SAF may give you a schematic if you tell them why you want it, that design is really long in the tooth now, I don't think they would be concerned about someone copying it any more. Besides, they copied it themselves from Saftronics years ago. 



> ... And by the way, since when is "1960 era" old!


Seriously.... :icon_eek:


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## LARMGUY (Aug 22, 2010)

Long start time for any piece of electronics aways point to caps. 1960's original capacitors? Replace it.


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## Wirenuting (Sep 12, 2010)

LARMGUY said:


> Long start time for any piece of electronics aways point to caps. 1960's original capacitors? Replace it.


LoL, the 1960's comment was referring to my young start buttons.


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## LARMGUY (Aug 22, 2010)

Wirenuting said:


> LoL, the 1960's comment was referring to my young start buttons.


  :thumbup:


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## peloflex (Jan 18, 2013)

If it was trying to find that bug, I would be asking quite a few questions to the operators, they always have valuable information, my first question would be, since when is the machine acting up like that? Investigate and try to find out any related facts that might lead you to the actual cause. Another thing I would do is to time those 3 minutes as precise as possible, is that time always dead on 3minutes? or does it float up and down? lastly, to dissipate the thermal possibility, throw some heat into the suspicious components, have a heat gun handy and gently heat up one component at a time before start time, see if the 3 minute change. 
I have some funny stories... best of luck!


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## JRaef (Mar 23, 2009)

Or, spend 10 minutes swapping out the board.

When I did training on soft starters for users and maintenance techs, I would tell them to just think of it as a starter. In an electromechanical starter, what can go wrong? A bad coil or bad contacts. If the coil burns out, you replace the coil (after taking prudent steps to find out why of course). if the contacts wear out, you replace the contacts. In the smallest starters, it's not even worth doing that, just swap out the whole thing.

In a soft starter it's almost the same. There are two things that can go wrong; the SCRs, which are like the contacts, and the control board, which is like the coil. If the board is bad, swap it out. If the SCRs are shorted, swap them out. If it's a cheap small one, change out the whole thing. Same rules, same responses. Don't over think it, it's not worth it in the long run if down time is of any value.


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