Motor Control for Pump

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topend

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I've installed a 10 hp 230v 3 ph pump motor on a Size 2 reversing starter. The start-up amperage(torque) trips my feeder breaker every time. I'm guessing I need some sort of "soft start" device. Any advice?
Thanks,
Rich
 
What is the starting and running amp rating for the motor?
What type and size of breaker are you using?
Is the pump rated to start with the pump already primed?
Let's look at that before putting on a soft-start or VFD.

There may be an issue causing this other than the feeder breaker being sized too small.
 
pump

pump

topend said:
I've installed a 10 hp 230v 3 ph pump motor on a Size 2 reversing starter. The start-up amperage(torque) trips my feeder breaker every time. I'm guessing I need some sort of "soft start" device. Any advice?
Thanks,
Rich
Click to expand...

Need more info. Also what kind of contractor are you???:-?
 
???

???

More Information would be nice here are a couple of observations
what size breaker did you install? Is it sized at 125%, or 250% of the nameplate fla, also you indicated that this is a 230v-3ph motor are you running this motor on a 208v system if so what size conductors and what length of wire, basically what is the voltage at the motor if you voltage at the motor terminals is too low due to any voltage drop this might be causing your problem if I remember correctly the motor is rated plus / minus 10% and the voltage is allowed to flucuate from 10% plus / minus in combination with the utility and building power if that is the case and the 230V motor requires 207V and the low end to operate if you are on a 208v system and you are getting 200-207 volts this could be the porblem as the system will be allowed to drop as low as 187.2v (10%) a 200v class motor might solve your problem, also check the breaker / conductor size, just my opinon.
 
Does the breaker trip as soon as the contactor pulls in or does it wait 3-10 seconds? Instantaneous trip means inrush current is too high for the breaker and a bigger breaker may be needed. A time delayed trip could be from the pump taking too long to get up to speed.

What amps does it draw and for how long?
Is the pump spinning in the correct direction?
Is the pump valving correct so it is not starting up under heavy load?
 
breaker setting

breaker setting

In my experience the question by FNCcna is often the key. As best I can tell the IT is factory set to minimum. If it is adjustable on this breaker I'd bet that would solve the problem (assuming the breaker is properly sized). I've seen it so often
 
This motor should only pull approx 28 amp with a locked rotor of 168 amp . The code allows up to a 200amp instantaneous trip or 70 amp inverse time breaker on this . If your breaker is a lot less I would try increasing.
 
just got back

just got back

thanks to all who have responded.
feeder circuit breakdown as follows... 30A breaker with 10 awg wire (approx 60') to 30A fused disconnect mounted next to to Size 2 reversing starter (10') to 10 HP 230v motor (27.5 fla).
The breaker is a in plug-in loadcenter w/ no adjustable trip feature. It trips after a couple of seconds at around 120 amps of inrush (the fuses have never blown). The starter is one the the customer had laying around and is reversing-type to suck liquid out of the piping apparatus back into the tank.
I don't have any more motor info at this point.
 
thanks to all who have responded.
feeder circuit breakdown as follows... 30A breaker with 10 awg wire (approx 60') to 30A fused disconnect mounted next to to Size 2 reversing starter (10') to 10 HP 230v motor (27.5 fla
Click to expand...
I believe you just answered your own question.
With an FLA of 27.5 amps your breaker is only sized at 110%. I suspect whoever installed this origionally did not understand the code. He sized the breaker and wire to the 30 amps, disallowing any inrush. You need to upsize your wire and the breaker and the fuse , per article 430.
What Class fuse is in there CLass RK-5, RK-1, J, H ?

I'm still shaking my head over this one.
Just my $.02
 
I would typically use a 50 amp breaker for that motor in an MCC and fuse it for 40 or what the manufacturer required.

I think we have a solution to your problem here!
 
An added note: The "Starter" that has been "laying around" should have either heaters or an adjusable trip range overload. Check to see that the OCP on the starter is sized correctly for protection.
 
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