pump drawing low amps
pump drawing low amps
(OP)
Hi
Please can you help, i have a 1 ph 240v heating pump.
The full load current is 2.7 amps however its only drawing 1.9 amps. I also dont get the correct differential accross the pump, the measured pressure is lower than the design.
Please can you advise where is should be looking in order to resolve the situation.
Regards
Please can you help, i have a 1 ph 240v heating pump.
The full load current is 2.7 amps however its only drawing 1.9 amps. I also dont get the correct differential accross the pump, the measured pressure is lower than the design.
Please can you advise where is should be looking in order to resolve the situation.
Regards





RE: pump drawing low amps
If it was 3ph I would suggest that it was running backwards.
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Plymouth Tube
RE: pump drawing low amps
Might be as simple as that the pump was designed with a bit of safety factor?
You'll never see a pump motor loaded to full load amps on the nameplate...
If you can give more specifics -- are you getting insufficient flow, for example, perhaps give us a diagram, the purpose of the pumping loop, etc...
Best to you,
Goober Dave
RE: pump drawing low amps
the design duty was 1.9 l/s@ 70 kpa. The actual site measuremnts are 1.51 l/s@ 65 kpa and drawing 1.9 amps
regards
RE: pump drawing low amps
I guess the more interesting question is why the flow rate is less than design. That could be something as simple as suction pressure is less than design or as complex as scale on control surfaces. Without knowing the suction pressure near the eye of the impeller it is pretty pointless to speculate.
David
RE: pump drawing low amps
Johnny Pellin
RE: pump drawing low amps
RE: pump drawing low amps
RE: pump drawing low amps
To really sort out the problem you need to measure the head across the pump from inlet to outlet - at the moment you don't have any idea what is happening on the inlet side - you could be incuring a high inlet head loss.
RE: pump drawing low amps
Do you have a pump curve? what should the rated pump BHP be compared to motor HP? You're still about 70% FLA at 1.9 A. Check for blockage at the suction/inlet as suggested, the pump may be starved (low NPSHa) and running off the end of the curve. If you have a discharge valve, try throttling the pump back on the curve.... record amps, then open at various settings (25% open, 50% open, 100% if you can, etc) and record amps. If the pump horsepower curve is continuously rising towards higher flows, amp draw should also increase as the valve is opened. If amp draw decreases as you open the valve, and discharge pressure decreases signifigantly, then suction pressure is likely too low
Did you know that 76.4% of all statistics are made up...
RE: pump drawing low amps
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RE: pump drawing low amps