Backyard Aquaponics
A place to discuss aquaponics

Nova, you are right it was late last night and i was going to put the second installment in

If you open up one of your sub. pumps you will find that there is a coil encased in epoxy, and the impeller shaft has a permanent magnet around it.
It is diffent type of "ac motor"

I was going to ask someone to do the tests and your has confirmed my thoughts.

So, if it wasn't confusing enough people need to remember that the SMALL submercible pumps are different.

Probably the easiest way to get your watt rating is by multiplying the amps by the watts.

nova, can you do this and post back? it should work out VERY close to your measured power.

the plot thickens

From my knowledge of motors and pumps:
The power rating on the plate is what electricians use to determine wire sizes and thus must be the electrical power drawn by the motor.

If a motor measures significantly more power draw than the rating plate indicates , then it is most likely faulty. The most likely causes of this are bearings which are binding, or manufacturing faults / tightness (which will reduce after initial wear-in).

The rating plate which Steve attached, does indicate both ratings (power input and power output (shaft power)).

I hope this helps,
Tony

Tony, i'd have assumed that sparkies would have used the AMP rating on the plate to determine wiring size.

Everything after the first two lines i agree with totally. we determine the health of a motor by taking a reading of the amps.

I can almost 100% guarantee that Permanent split phase (run capacitor) motors as used in sump pumps et. al. will state shaft power if there is only one power listed.

You know what would be great?

Can EVERY ONE who has a pump jot down the;
VOLTAGE
AMPS
WATTS
TYPE OF PUMP

i'm going to predict that the VxA will = the W on all the small submerc. pumps and power heads, as well as almost all air pumps.

And that all of the larger pumps like sump pumps etc. will seem to be out by about 60%.

Very interesting stuff!!

Hi Steve,
Here`s the specs on my stainless steel jet pump. When i get chance i`ll put the meter on it to see what current it actually draws.

In that pic V=220, In = 2.6

P = V*I = 220*2.6 = 572 != .460 kW

But wattage can be quoted in lots of different ways. Max, average, rms, etc. Voltage stays more or less constant with your power supply, amperage can vary drastically based on internal construction as well as load.

you've already posted a pic of the plate from one of my pumps, Ebara

Does anyone have the plate data for a Global Pond 2 pump? I don't want to pull the pump from the tank if I can avoid it

Edit:
Bertha, Global Pond 2 made by Leader Pump Group, Italy - submersible
Volts - 240V
Amps - 3.3A
Watts - 700W

Here's what I know about motors.

There are several tricks to reducing power draw for motors. Well, 3 that I know of.

If a motor is not fully loaded then it generates heat. If a motor is only under a 50% load then you can reduce power draw by 50%. Air blower motors are a good example of motors that are not loaded to horse power ratings.

A horse power is 746 watts. Motors vary on efficiency. When slowed down they loose efficiency. When motors are turned faster than the name plate speed the become generators (thats the way the power company does it).

The power saving modes I know of:
1) power factor correction (saves up to 25%)
2) voltage reduction (saves up to %50)
3) resonant tank circuit (saves up to 60%)
If anyone wants to know any details just pm me.

i guess what i was trying to get at was that the Kw or HP rating is the power developed by the motor, not the power consumed from the electrical grid. As long as we're all clear on this and use the P=VxI formula to arrive at our consumption figures

You just gotta laugh... just read the original post on this thread

string

This pump only requires your time and some calories for operation

Yeh, but try working out the cost of energy in ... conversion to energy required to operate.... to energy used on that one DRD

I reckon I'd need at least a six pack a day to live with that pump..... that's about $70 a week at least

home brew Rope

LOL, you guys!

but then you'll have to carbon ofset the fermentation process, J