3 phase Submersible Pump/Motor protection

[jc3l]

Here is our application: 3 phase 460V 150HP submersible pump/motor Namplate Data: amp = 220 SF = 1.15 PF = .880 kVA code = J
Continuous Duty Squirrel cage Rotor Design ? Size 5 starter and 200A fused disconnect (200A Frame) is what is presently in place and was used on the previous motor.

Is the sizing of motor protection (DE Fuse), wiring, overloads different for a submersible? Based on Nameplate Data the FLA is higher than a standard pump motor. Generally table 430.250 is close to the nameplate amperage but this is not the case here. Any guideance would be appreciated.

Looking to do it right

 

[ptonsparky]

The pump mfg usually has details for overload protection etc in their installation instructions. Class 10 ovrload protection IIRC.

 

[augie47]

In my experience submersible pump motors often have significantly higher current draw than their equivalent standard frame motors.
I agree with Tom in that I would see what the manufacturer had to allow.
Even at Table values, much less for you application, 200 amp disconnect would not meet Code for a 150HP motor (430.110)

 

[ptonsparky]

A Franklin pump had a SF amps of 219. I looked an hour or so ago so don't hold me to the exact number, with FLA of 190. I do not size overload protection on SFA but Pump installers are notorious for it.. Even so a 200 is cutting things close.

 

[weressl]

A Franklin pump had a SF amps of 219. I looked an hour or so ago so don't hold me to the exact number, with FLA of 190. I do not size overload protection on SFA but Pump installers are notorious for it.. Even so a 200 is cutting things close.

There are two reasons why submersible pumps have higher amperage than high efficiency, squirrel cage, NEMA design B, EPACT motors. One is the forced construction of long and skinny rotor/stator does not optimize the magnetic design. Secondly the 'ambient' temperature is generally taken to be less in the submerged, underground application than aboveground air of 30-40C.

 

[Jraef]

You only use the NEC tables to select the MINIMUM conductor and SCPD protection. If the motor nameplate EXCEEDS the table value, you must use that.

Overload protection must ALWAYS be based on the motor nameplate information. Then in the case of submersibles, I agree with ptonsparky, they are usually required to be Class 10 quick trip. I know for a fact that is the case with Franklin pumps, but some of the smaller ones need Class 5. You must check with Franklin to be sure. Also with them, sometimes they require you to use their Subtrol overload and protection module, otherwise you might void or diminish the pump warranty.

 

[GoldDigger]

Secondly the 'ambient' temperature is generally taken to be less in the submerged, underground application than aboveground air of 30-40C.

Which is why a submersible pump motor can burn out fast under zero load if the water level drops too low to cool it. Low water protection can be more important than overcurrent protection if the well has capacity problems.