Looking at sump pumps...found 2 pumps... both 1/2 HP, but one nametag said 13 amps and the other said 6.5 amps. Both 110v units. Is it possible to have 2 pumps, both with the same HP rating, so different in amperage?
Pump HP and Amperage
- Thread starter bmwpower
- Start date
Jaguar Fan
Well-known member
I don't think so.
1 horsepower = 745.699872 watts, according to a quick google search.
So, 1/2 HP should be ~327.85 watts.
Watts = volts * amps
so... the 1st pump is 13 amps x 110 volts = 1430 watts
and the 2nd pump is 6.5 amps x 110 volts = 715 watts
I think it takes some creative rounding to make either one of them a 1/2 HP pump. Maybe those amperages listed are peak at startup but the motors each drop down significantly for sustained operation (I'm just making this up - don't know if its true).
But maybe someone who is more knowledgeable can correct me.
1 horsepower = 745.699872 watts, according to a quick google search.
So, 1/2 HP should be ~327.85 watts.
Watts = volts * amps
so... the 1st pump is 13 amps x 110 volts = 1430 watts
and the 2nd pump is 6.5 amps x 110 volts = 715 watts
I think it takes some creative rounding to make either one of them a 1/2 HP pump. Maybe those amperages listed are peak at startup but the motors each drop down significantly for sustained operation (I'm just making this up - don't know if its true).
But maybe someone who is more knowledgeable can correct me.
Last edited:
Torque1st
MEMBER EMERITUS
There are a lot of "funny" HP ratings used on consumer products.
In the case of the 1/2HP pumps you mentioned in post #1 it is highly likely there is some misprint caused by translations from Chinese and metric units.
Check out this pump:
http://www.grainger.com/Grainger/items/3XU84?Pid=search
Item number 3XU84
The pedestal pumps are more $$$ but they last a long time.
In the case of the 1/2HP pumps you mentioned in post #1 it is highly likely there is some misprint caused by translations from Chinese and metric units.
Check out this pump:
http://www.grainger.com/Grainger/items/3XU84?Pid=search
Item number 3XU84
The pedestal pumps are more $$$ but they last a long time.
That pump look awesome, but 5 bills...ouch. TEFC motor would be nice.
Actually, at Home Depot I think the pedestals were a little cheaper.
Is yours noisy?
Torque1st
MEMBER EMERITUS
I can hear it because the pump bearings are a mite worn. Most of the noise is from the pump not the motor. The high $$$$ for a replacement is why I keep repairing the switch. I just hope it lasts a while longer. I will be replacing it with a sewage pump next year. I have a submersible pump I can drop in if it fails. I test my sump pump every month or so.
One of the problems with submersible pumps is that the electrical connections go bad from water seepage. Water gets in everything... Water migrates along potted wire connections. Water migrates thru materials, most organic materials are water permeable. When moisture gets inside the housing leakage current increases which will trip GFI circuits. I wish I had a nickel for every submersible pump that was replaced because the basement flooded after the pump "obviously" failed.
One of the problems with submersible pumps is that the electrical connections go bad from water seepage. Water gets in everything... Water migrates along potted wire connections. Water migrates thru materials, most organic materials are water permeable. When moisture gets inside the housing leakage current increases which will trip GFI circuits. I wish I had a nickel for every submersible pump that was replaced because the basement flooded after the pump "obviously" failed.
Torque1st
MEMBER EMERITUS
I am installing a 3/4 bath in the basement. The house used to be on a septic system so the main sewer line is 4' above the floor.
D KRAGER
Well-known member
They get by with that rating most likely by rating the peak hp rating. Not the running hp rating....... Kind of like most 60gl air compressors, they say 5hp motor, but that's peak hp rating, they are really 3hp while running.
Torque1st
MEMBER EMERITUS
-And it takes continuous HP to compress air. That peak HP can help the compressor get past that last little "hump" as the tank is building pressure but otherwise it is meaningless.
I talked to one of the Engineers down at NEMA and they get away with it using instantaneous HP related to breakdown torque. The consumer goods manufacturers don't have to conform to NEMA standards. Just look at that "5HP" circular saw or shop vacuum running on that little 18AWG or maybe even a 16AWG cord, -wear your ruby slippers, tap your heels and wish...
On consumer compressors just look at the amp draw to approximate the real HP.