Pump Motor Overheating - High Amps

captjake

Member
Aug 30, 2010
23
PLEASE, PLEASE, PLEASE help me. I'm at my wits end.

Hayward Super II Pump
1hp Marathon motor running on 110V, 12.6A
C1200 filter

In short, motor under load is drawing 18-20A. Motor will run for a while, thermo will pop from overheating, cool, and then restart.

Called electric company. No known voltage drops. Wires into house checked. All tight.

Electrician called. Voltage drop at timer. New wire run from timer to motor. New 20A breaker installed at main panel. Voltage back to 118-122V. Still drawing 20A. Electrician said the motor was bad.

New 1hp motor installed. Still does 18-20A under load when pumping water. 10-12A without load. New impeller, shaft seal, gaskets, etc. Good water flow, clean basket, no obstructions. I've replaced everything that can be replaced.

I'm out of ideas. What am I missing...??!!! Please help...!!!!!
 

JohnT

Admin
Mod Squad
TFP Expert
Apr 4, 2007
9,476
SW Indiana
Welcome to TFP.

Well, the obvious first question is are you sure the impeller is designed for a 1HP motor?

What is the service factor (SF) of your motor?

Filter pressure reading?
 

Ohm_Boy

TFP Expert
May 1, 2007
1,344
Orlando, FL
When you say 10-12A with no load, how are you getting no-load? No water? Pipes open? Motor disconnected from pump?

If a meter shows 120VAC nominal at the motor terminals, then I would pull the motor from the pump and run it uncoupled, and check the draw with the shaft free to spin. I wouldn't expect over about 5 amps. If it higher, then it's on the motor side, else it's the pump.
 

captjake

Member
Aug 30, 2010
23
No load means the motor is uncoupled from the pump...same as you described. Motor has juice and spins no problem. Will double-check on amp output and repost, but fairly certain it draws around 10A.

How can it be the pump? Can you elaborate, please? Impeller, diffuser, and casing. That's all there is to it. All new parts. No diaphragms, nozzles, bellows, etc. No signs of damage to the impeller or rings. What could cause the increased friction or load on the pump?

Motor is brand new. Old motor was producing the same amps, but thermo may have been burned out.
 

Ohm_Boy

TFP Expert
May 1, 2007
1,344
Orlando, FL
With a 10A no-load draw on 120VAC, it ain't the pump.

10 amps at 120V is pretty much a full horsepower, around 60% efficiency or so. That's what it should be drawing while pumping at capacity.
It certainly seems that something is awry with either the voltage supply or the motor.

Verify the actual voltage and current at the motor.

Maybe it's me, but I expect an unloaded motor to draw around maybe 6 amps uncoupled. Any chance you can try another motor?
 

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
23,063
SouthWest Alabama
I agree with Ω_♂. That motor should pull about a third of the full load amps uncoupled.

112v is a little low but shouldn't cause that kind of current draw.
 

JohnT

Admin
Mod Squad
TFP Expert
Apr 4, 2007
9,476
SW Indiana
I'd try running the motor on a short cord at an outlet closer to the panel. Seems the only thing you haven't changed is the wiring from panel to pump. If you aren't comfortable messing with that, a motor/starter/alternator shop could probably spin it up on a bench and measure the current for a reasonable fee.
 

captjake

Member
Aug 30, 2010
23
When you say panel to pump, do you mean from the main breaker panel to the pump?

And, do you mean a bench test with a pigtail attached? Are you thinking the wire run from the main panel to the pump is damaged?
 

JohnT

Admin
Mod Squad
TFP Expert
Apr 4, 2007
9,476
SW Indiana
captjake said:
When you say panel to pump, do you mean from the main breaker panel to the pump?

And, do you mean a bench test with a pigtail attached? Are you thinking the wire run from the main panel to the pump is damaged?
Yes, main panel to the pump.

I honestly don't know, but it seems like you've eliminated everything else. Running a bench test will tell you if something is going on with the wiring.
 

captjake

Member
Aug 30, 2010
23
Will do bench test and report back. The motor company is going to freak. Two bad motors in less than 3 months...?
 

captjake

Member
Aug 30, 2010
23
Bench test complete. Approximately 6 feet from the main breaker panel.

118V
8.8 - 9.3 A

What do you think?
 

captjake

Member
Aug 30, 2010
23
And just for giggles, I switched the setting back to 220 and ran it under load.

118V
13.2A

Ran for about 10 minutes and overheated.
 
G

Guest

Mechanical Timer? Running 10 AWG that distance would probably be better, but I think your fine with 12AWG? I think your losing about 3 volts with that distance of wire. Did you change the timer? or for a quick check can you bypass the timer and hard wire to the pump??
 

captjake

Member
Aug 30, 2010
23
Yes, original mechanical timer. I did disconnect the light transformer thinking that maybe causing an issue. No change. I think I did bypass the timer previously but will try again in the morning. Thanks.

After that, any ideas?
 

Other Threads of Interest