Long winded story look at the bottom line if you are short on time.
OK I got a call from the local motor shop. They sold a 125 hp to replace a 100 hp about a month ago. The system will run under a load no problem. Every now and then the system will shutdown with a fault. The plant guys just reset the fault without looking at what it was.
I started trouble shooting first looked for mechanical issues. The bearings where 100~116 degrees F. I could turn the load by hand no problem. So I started looking at the controls. This system has a Westinghouse reduced voltage motor starter. I used a the only amp probe I had with me that was a 300A on startup we pegged the full scale. Once the system was up to speed just turning a flywheel the current was 45A. The wave forms looked like a nice 60Hz clean wave, 479VAC on all legs. All looked OK
Then the circuit board LED blinked and the voltage dropped to 230 and the wave form started jumping around. The wave form had some huge spikes in them from 60~90 Hz. in a random pattern like noise. The current went from 45A to 25A. I was at a loss the system looked like it just nosed dived.
I call technical support and the first question was how new is the motor and when did the problem start? I it a permium eff motor? I said yes premium and 1 month old. "turn the second DIP switch OFF on the thirs bank of switches" is what the tech told me to do. It is the energy saving mode. They reduce voltage after 10sec of light load. "These new motors are giving us problems with the old starters, a standard eff. motor will run no problem in our systems" was another comment he tossed out.
Look here if you jumped around the long details.
Has anybody has issues with the Premium Eff motors and older drives or starters causing problems?
OK I got a call from the local motor shop. They sold a 125 hp to replace a 100 hp about a month ago. The system will run under a load no problem. Every now and then the system will shutdown with a fault. The plant guys just reset the fault without looking at what it was.
I started trouble shooting first looked for mechanical issues. The bearings where 100~116 degrees F. I could turn the load by hand no problem. So I started looking at the controls. This system has a Westinghouse reduced voltage motor starter. I used a the only amp probe I had with me that was a 300A on startup we pegged the full scale. Once the system was up to speed just turning a flywheel the current was 45A. The wave forms looked like a nice 60Hz clean wave, 479VAC on all legs. All looked OK
Then the circuit board LED blinked and the voltage dropped to 230 and the wave form started jumping around. The wave form had some huge spikes in them from 60~90 Hz. in a random pattern like noise. The current went from 45A to 25A. I was at a loss the system looked like it just nosed dived.
I call technical support and the first question was how new is the motor and when did the problem start? I it a permium eff motor? I said yes premium and 1 month old. "turn the second DIP switch OFF on the thirs bank of switches" is what the tech told me to do. It is the energy saving mode. They reduce voltage after 10sec of light load. "These new motors are giving us problems with the old starters, a standard eff. motor will run no problem in our systems" was another comment he tossed out.
Look here if you jumped around the long details.
Has anybody has issues with the Premium Eff motors and older drives or starters causing problems?