Just wanted to keep updating this thread.
We were using a 350 KW generator to start the 74 KW pump motor direct online and were getting significant voltage drops to the point of the UPS engaging in the portable control cabin.
We then changed to a 175 KW generator having a permanent magnet...
Would the rule of thumb you are suggesting apply to a genset whether it has a permanent magnet generator as well? We were using a genset that was approximately 2x motor load compared to the next closest size genset size without a permanent magnet generator of 300 KW in order to start the motor...
jraef - I appreciate that you're skeptical as I have an electrician that is as well since he's used to the rule of thumb to size the generator for 3x motor running amps. This is where I see the value of the permanent magnet generator to provide the necessary excitation for the start cycle. I...
I have received feedback from the rental company that the 150KW generator we were using had a permanent magnet generator to DOL start the 100 HP electric motor.
It seems to me that using a permanent magnet generator is the most appropriate since we can significantly reduce the generator size...
Marke thanks for the quick reply. The motor is starting a triplex pump. There is normally little or no pressure when starting the pump. There is also a small centrifugal boost pump and a small hydraulic pump that run off the generator but normally don't start at the same time and are low power...
Mark thanks for the quick reply. The motor is starting a triplex pump. There is normally little or no pressure when starting the pump. There is also a small centrifugal boost pump and a small hydraulic pump that run off the generator but normally don't start at the same time and are low power...
I have the following motor and would like some direction on sizing a generator.
100 HP motor
460V 60 HZ, 129 FLA
PF 82
Nema kVA code H
Typical starting current 832 Amps according to spec sheet.
Direct online start
The motor starts and gets up to full running speed under no load or virtually no...
The service factor is 1.0 I have convinced everyone that we need a larger cable and a 250A breaker. Hopefully they will put the right type in. The cable is quite short, approximately 50 meters. I still haven't had an explanation from the rig why a 300A breaker was on a 125A service but...
As you may have guessed - this is more like putting the cart before the (dead) horse :-) As mentioned the system I was given which was 125A with a 300A breaker. Don't ask me what they had plugged in before - probably something with a short! Best I've managed to get them to do is reduce the...
If a 184A motor is started under at essentially no load (starting a pump at zero pressure) can this be done using a 125A breaker (or 100A) when started directly on line or with a soft starter? If the load then increases or there is a failure then the breaker would be sized properly for the cable...
How is the wiring a violation? 184A motor on a 125A system? I can request that the breaker be reduced. With a 184A motor expected to draw approx 100A max. could the breaker be reduced to 125A or would starting current cause a trip and need to be something above 184A?
Thanks for the information. I should have said limit to 90A / approximatley 55 KW, which would be about 1400 psi on the pump, so as not to overload the 125A cable and plug. I can use a pressure relief valve for this so indirectly limit the load on the motor. I realise this isn't the best...
I have a 440V 60 hz 184 amp motor (110 KW). The power supply is 460V (on an offshore drilling rig) with the cable and plug rated for 125 AMP, but has a 300 AMP breaker. The motor is connected to a pump and I expect we will not require more than 90 KW and will limit the pressure output of the...