- #1
nlaham
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I get very confused with AC electrical service, I'm a mechanical engineer so these things just confuse me. DC makes perfect sense to me.
Anyway,
I need to supply a single phase motor with 230V (the specs say 230V +/- 10%), so that would make my tolerance 207V to 253V. The motor is for a variable speed pump that can be adjusted by a variable frequency drive to adjust the RPM output. It has terminals for Line1, Line2, and Neutral
Anyway, the building has 3 wires, L1, L2, and N. When I measure across L1 and N, or L2 and N, I get 120V. When I measure across L1 and L2 I get 208V.
So in theory I am withing the tolerance using 208V single phase, but the motor is starting to receive an over-current alarm lately and shuts down (it has operated for 6 months before with no problems or alarms). Any idea why this would start happening now?
Also, how would I get 230V single phase power? And where does this 208V come from? I assuming the 208V is coming from a Wye Three-Phase system, and for some reason I only have two legs and a neutral at my point of work. In theory, I could get 240V single phase from a Delta Three-Phase configuration by going across poles, right? But in order to hit 230V on the dot, I would need a transformer I think?
I'm just worried that since I'm on the low side of my voltage tolerance it's been drawing a lot of current to the motor and thus maybe burnt it out quicker than it normally would have lasted. If the motor started to degrade from this, wouldn't it increase the resistance over time and try to draw even more current? Maybe that's why the alarm started recently?
Any help or comments would be awesome.
Thanks,
Nick
Anyway,
I need to supply a single phase motor with 230V (the specs say 230V +/- 10%), so that would make my tolerance 207V to 253V. The motor is for a variable speed pump that can be adjusted by a variable frequency drive to adjust the RPM output. It has terminals for Line1, Line2, and Neutral
Anyway, the building has 3 wires, L1, L2, and N. When I measure across L1 and N, or L2 and N, I get 120V. When I measure across L1 and L2 I get 208V.
So in theory I am withing the tolerance using 208V single phase, but the motor is starting to receive an over-current alarm lately and shuts down (it has operated for 6 months before with no problems or alarms). Any idea why this would start happening now?
Also, how would I get 230V single phase power? And where does this 208V come from? I assuming the 208V is coming from a Wye Three-Phase system, and for some reason I only have two legs and a neutral at my point of work. In theory, I could get 240V single phase from a Delta Three-Phase configuration by going across poles, right? But in order to hit 230V on the dot, I would need a transformer I think?
I'm just worried that since I'm on the low side of my voltage tolerance it's been drawing a lot of current to the motor and thus maybe burnt it out quicker than it normally would have lasted. If the motor started to degrade from this, wouldn't it increase the resistance over time and try to draw even more current? Maybe that's why the alarm started recently?
Any help or comments would be awesome.
Thanks,
Nick