ABB REF542 Plug Motor Feeder Protection Relay

The question comes to mind, why on earth would you want a way to quickly reset a protection relay?

Why not spend your time more wisely by trying to correct the high temperature problem in an effort to run your motor at a more acceptable temperature range? You made no mention of the ambient temperature, but lets assume 40c. So then you are saying the motor is running 60c above ambient???

It seems to me that if you correct the problem at hand, then you will no longer have the symptoms to worry with. Your motor will last much longer as well

This is the compressor motor is heart of the chemical plant, Once the motor trip more than one hour,Plant will shut down & stop production.

The motor is operate at full load condition all the time, Is I modifier the cooling fan to increase cooling efficacy and the motor efficacy will drop.

If I increase the temperature to 145 deg C, the motor insulation will be deteriorate and reset time will be take longer .(10 deg increase on the electrical equipment , the life span will drop 50%.)

Only way to restart the motor and inform the process department to reduct the output, keep monitoring the load current and plan to order the large motor.

K2,

You state a compressor, I will assume we are talking about compressed air. If the motor is of the correct size for the compressor at the moment it should be able to handle full load 24/7 as long as there are no mechanical deficiencies changing the equipments parameters.

One thing you may look at is the delivery pressure, if you could lower this even 1 bar it would help enormously. I have had this situation on a rig recently where all three Atlas Screw Compressors were tripping out and couldn't find anything out of the ordinary until I found where someone trying to improve the capacity unknowingly raised the pressure settings over the manufacturers recommended point. I lowered the pressure and everything went back to normal.

Another point is that you are obviously in need of a second unit. You could normally run both units to reduce demand and also have a redundant unit so you could maintain one or the other without compromising the plants supply.

Again, I can only assume what your situation is with limited information at this point.

Hi,

First check if your RTD protection is working correctly.

Decide if you need to trip on RTD temperature .

When it trips you need to cool down till it is ok to restart. You wrote " once the motor restart immediately" , are you doing a emergency restart, is this required for you application?

Motor Relay wont lock up the temperature if you allow enough time for cooling. We use SEL motor relay and it works good and it has thermal model also, I think your relay works fine.

And Investigate why your motor is getting heated so much. How long are you running it? what is the staring current? rated current? how long it starts?

The motor RTD is tested & work perfectly.

The setting for the RTD set at DCS is trip at 145 deg C, But before the motor RTD trip and the ABB relay is already trip.

RTD is measure direct for the motor winding , and the ABB relay is convert the load current to the temperature by mathematics calculation function. the trip value may not be same.

The temperature show at the ABB relay is the mathematics caculated value, the actual motor operating temperature is lower than relay show.

better set dcs trip at 120 deg.then the pickup setting on the thermal replica relay can be increased by say 5% and observe the response when steady state is reached.a precise safe setting can be determined.such critical situations better allow 15% spare capacity for the motor

Same If I change the RTD- DCS setting to 120 deg C.The compressor motor stop by the RTD-DCS function and restart the motor immediacy,the high motor temperature trip will come in.

I need to know how to carry out quick reset the high motor temperature (to clear the old value inside the protection relay) keep the motor running.