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Using a Surplus Motor to Solve a Problem - 1250HP, 394RPM, 4000v Vertical Motor Case Study


We received a phone call from a motor repair shop that had a power plant client that was under a unit wide shutdown due to a breakdown on a 1000 HP 394 RPM 4000v GE Vertical Solid Shaft Pump Motor. With a replacement motor 9 months out, and a completely destroyed, practically unrepairable original motor, they were asking - "Can you help?"

Lucky for this customer, we had a potential surplus motor in our inventory. Would this work? Below you will see some of the steps and comparisons that were taken to perform this evaluation.


Mechanical Similarities

Starting with the mechanical similarities, base diameter, shaft diameter and shaft length on the customer's motor were equal to the HECO motor. These aspects of the motor did not need to be adjusted.


Mechanical differences

We then looked at the Rabbit Fit or “AK” Dimension. The customer's AK was a 54” male and we had a 51” female, so we created a ring to match the male piece, allowing our motor to fit right onto the pump. Take a look at the picture below to see the difference in the AK.

The next obstacle was adapting to the Bolt Circle Diameter or “AJ” Dimension. The customer's AJ was 62” while ours was 59”. Removing the bottom end bell and adding new bolt holes, enabled us to match the customer’s AJ. The figure below shows the adjustments that were made to the HECO motor in order to match the customers's AJ.
Next, the customer's motor had a 13.5" Kingsbury thrust bearing and our motor had a 18" Kingsbury thrust bearing. We kept the bearings in the HECO motor to allow for a larger thrust capacity.
Motor Enclosure
The HECO motor, had an enclosure without louvers, so we needed to add them to match the customer’s motor. Custom louvers were created and installed that exceeded the level of protection provided by the GE Motor. Before and after pictures at the bottom of the page show this modification.

Electrical Comparison

The customer's 1000 HP motor pulled 146 Amps at full load. Our 1250 HP motor pulls 173 Amps at full load per name plate. At 1000 HP, HECO's motor was calculated to pull around 139 Amps at full load after the repair.

We then looked at the KVA codes to identify the locked rotor amps. The customer's motor was a code H and took in 1,024 Amps and the HECO motor was a code F pulling 1,010 Amps.



Both motors had 100 Ohm Pt. Winding RTDs. The customer had Bearing Thermocouples and we had 100 Ohm Bearing RTDs which we replaced with the equivalent Bearing TCs.

That completes this motor reconstruction case study. We were able to send out a fully refurbished surplus motor in order to get our customer back up and running - All in the matter of a few days versus multiple months!


                            Original Motor                                                      HECO's Replacement



Download How To Get The Righ Electric Motor


Geoffrey Brewer

HECO - All Systems Go



About the author:

Geoffrey Brewer  is the Director of New Equipment Distribution at HECO - All Systems Go. Geoffrey lead HECO's team on replacing motors with new or surplus options. From NEMA T-Frame motors to large, custom Above NEMA frame motors, Geoffrey and his team lead the charge for HECO.

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