Ambient temperature too high for Motor Starter

[Vanece]

Hello, first time poster here. I have 85 of ABB's motor starters model 325 2.5-4A and the ambient temperature is too high for them during the summer causing them to falsely trip (above 104?F in TX). They are rated the standard 40? C from what I can tell on the product data sheet on page 5 (linked below). So my question is can anyone recommend a replacement that matches all the specs of this motor starter, but has a higher operating ambient temperature? I am a technician, not an engineer so while I could match the bullet points of another product I don't want to violate any code or safety aspects. I believe this is the correct forum for the question, apologies if not. Application is for a generator cooling fan motor on commercial wind turbines. There is also an HK-20 auxiliary contact that will likely need replacement with the new MS since they will likely be incompatible. Picture of current unit as is attached. Thank you for any feedback and sorry for the long post.

http://www05.abb.com/global/scot/scot209.nsf/veritydisplay/0015f49c150eb4d1c1257c7e0030dfca/$file/2CDC131046D0201.pdf

 

[GoldDigger]

Can you confirm that the overload/overcurrent is what is tripping? If so, the only solutions I can think of are:
A. Increase the current rating of the thermal OL because the heat rejection of the coil has to decrease as the ambient temperature rises.
B. Find an OL which trips normally at a high enough temperature that the effect of ambient temperature will be correspondingly small.
C. Find an OL that uses only digital integration instead of thermal to implement the inverse time overload to match the motor damage curve.
That said, I do not know what is available for any if those alternatives.
Option A would probably require changing the OL coils or setting between summer and winter to maintain proper protection.
The problem is similar to that of a breaker panel in the hot sun.

 

[Vanece]

Yes, it is definitely the OL as trips occur only in high heat and fan motor operate and tests normally after resetting the OL. The motor is rated for 3A at 50 degrees C whereas the OL is only rated 40 degrees C while closed. I've contacted ABB and they do not make a MS that is rated above 40 degrees C according to one of their technical specialists. Option B definitely sounds like the one I want, but I'm having difficulty finding a 50 degree C rated MS. I've contacted A couple of big companies like Siemens but no progress as of yet. Any brand recommendations?

 

[Ragin Cajun]

iF THEY ARE IN ONE ROOM, PUT IN AIR CONDITIONING.

rc

 

[petersonra]

A lot of motor starters have overloads available that are not heat sensitive as they are electronic rather than thermal.

Are you absolutely sure that the overloads are tripping because of heat and not an actual overload?

The other thing you could try is a small fan blowing on the motor starters to dissipate heat just a hair faster.

The other thing is that the guy that sold you this equipment may well have some liability to make good.

 

[GoldDigger]

iF THEY ARE IN ONE ROOM, PUT IN AIR CONDITIONING.

rc

Most likely there is one in the cupola of each wind turbine, 100' or so above the ground. Peltier-Seebeck effect cooling for the starter housing might make more sense, since it would only be needed when the generator was running.
Hopefully the cooling would turn on long enough before the cooling fan was needed to allow the starter to hold. Just include a thermostat to keep the OL from being overcooled in the winter and compromising OL protection. There is a minimum temperature for the starter too.

 

[iwire]

Any chance the motors are equipped with winding thermistors?


If so maybe using those as OL protection would be the way to go.

 

[Vanece]

A lot of motor starters have overloads available that are not heat sensitive as they are electronic rather than thermal.

Are you absolutely sure that the overloads are tripping because of heat and not an actual overload?

The other thing you could try is a small fan blowing on the motor starters to dissipate heat just a hair faster.

The other thing is that the guy that sold you this equipment may well have some liability to make good.

I think the electronic overload will wind up being the best option. The fan could be the fastest patch. The "guy" is GE wind and there are several warranty issues in the fire and this one may go unnoticed as it's small scale, but I agree with your sentiment.

 

[Vanece]

Most likely there is one in the cupola of each wind turbine, 100' or so above the ground. Peltier-Seebeck effect cooling for the starter housing might make more sense, since it would only be needed when the generator was running.
Hopefully the cooling would turn on long enough before the cooling fan was needed to allow the starter to hold. Just include a thermostat to keep the OL from being overcooled in the winter and compromising OL protection. There is a minimum temperature for the starter too.

There are no air conditioning units utilizing freon, just fans. I'm all for them as it would be a major quality of life improvement for working conditions of both technicians and the equipment, but I fear the six sigma overlords may not go for a major upgrade project. That and the two cooling fans draw air out of the nacelle (cupola) largely wasting kwH spent on air conditioning. I'll investigate trying to make the Peltier-Seebeck effect work in this application as that sounds perfect, but the electronic overcurrent relay may work out best realistically. The minimum temperature is -13F which is not a concern in TX. Thank you everyone for your input, this is a very helpful forum.

 

[winnie]

Is this really a 'false' trip? The datasheet that you posted for the starter says 'Temperature compensation from -25 ? +50 ?C'. Looking up the term I found:
http://www05.abb.com/global/scot/scot209.nsf/veritydisplay/74cd796359e5e996c1257bf8002fdb72/$file/2CDC131060M0201.pdf

Page 13 describes the 'temperature compensation'. It seems that the trip current is _supposed_ to go down when the temperature goes up. The controller is set for 'Ic' the rated motor current. The device is specified to _not_ trip below 1.05*Ic, and _must_ trip at 1.2*Ic. But these values change with temperature. At 50C, it looks like the lower end of the trip range is 0.97*Ic.

If the motor is rated for operation at 50C, and the controller is 'compensated' based on 20C, then an applications engineer may be able to determine that a different trip setting is appropriate.

-Jon

 

[petersonra]

I wonder why GE is using ABB starters.

 

[Ragin Cajun]

Winnie hits it on the nail.

Has the OP measured the running amps on the fans at the higher ambients? If the OL's are set corectly, it sounds like the motor is actually in an overload condition.

There's more going on than just OL ambient temperature.

RC

 

[Jraef]

Is this really a 'false' trip? The datasheet that you posted for the starter says 'Temperature compensation from -25 ? +50 ?C'. Looking up the term I found:
http://www05.abb.com/global/scot/scot209.nsf/veritydisplay/74cd796359e5e996c1257bf8002fdb72/$file/2CDC131060M0201.pdf

Page 13 describes the 'temperature compensation'. It seems that the trip current is _supposed_ to go down when the temperature goes up. The controller is set for 'Ic' the rated motor current. The device is specified to _not_ trip below 1.05*Ic, and _must_ trip at 1.2*Ic. But these values change with temperature. At 50C, it looks like the lower end of the trip range is 0.97*Ic.

If the motor is rated for operation at 50C, and the controller is 'compensated' based on 20C, then an applications engineer may be able to determine that a different trip setting is appropriate.

-Jon

Bingo. Electrical protection trip devices are All generally calibrated for 40C, it just gives a common reference for comparison. So to that point, anything else you buy will be the same. But the actual maximum operating temperature on electro-mechanical devices like that is usually much higher, in this case 55 or even 60C. you just have to adjust the trip settings accordingly. Here is the relevant paragraph in the above link;

The manual motor starters are temperature compensated in accordance with IEC/EN 60947-4-1. Depending on the device, the temperature range is between -25 ?C and +55 ?C or -25 ?C and +60 ?C. For temperatures between +55/60 ?C and +70 ?C, the upper set value of the adjustment range has to be reduced by a certain factors. Please contact your ABB to get more information

.

So basically you got hold of a nincompoop at ABB when you contacted them for the help they suggested.