# dc pump and a li-ion help please

Discussion in 'The Projects Forum' started by suyash, Jan 11, 2015.

1. ### suyash Thread Starter New Member

Jan 11, 2015
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well here's the problem i have a dc motor pump brushed which i wanna run using a 11.1 v lithium ion battery which i have .the thing is the pump has to function for a minimum of 1 hour which works but the pump seems to heat up a lot and is probably consuming a huge amount of current also there is a burning smell so i just cut power. the pump is a 6-12 v one and i was wondering if there is anything like a circuit that can regulate the current consumed by the pump which ensures a longer life of pump and battery.is motor rewinding a efficient way to maybe reduce its current consumption because this pump has a very thick wire winding which would mean low resistance.
thanks for all and any help

Jul 18, 2013
10,872
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You are probably exceeding the load rating for that motor at 11v.
What is the nature of the pump? With a impeller style pump the current can be reduced by closing off the output side to some degree when this is due to overloading the motor by athe application having a wide open inlet and outlet.
This method would be preferable to using a lower voltage.
Gear pump will be opposite.
Max.

3. ### suyash Thread Starter New Member

Jan 11, 2015
8
0
its a centrifugal motor pump with radial in and axial out
but how am i exceeding the load if the voltage is from 6-12v and I'm at 11 v

Jul 18, 2013
10,872
2,528
This is not the same as a simple resistive load.
Just because you apply the rated voltage does not mean you are not going to exceed the rated torque (current)!
Simply, a DC motor is required to reach a certain speed for a given load in order for the generated voltage to oppose the applied voltage.
If the load too high, the voltage difference is great enough to allow the current to exceed the rating for the motor, if the load persists, it usually results in destruction of the motor.
Is the input and output sides relatively unrestricted?
Max.

5. ### suyash Thread Starter New Member

Jan 11, 2015
8
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you are right
i just pulled up the data sheet for the pump it seems the maximum allowable rated current is only .8 amp
and I've been using about 1600 mah battery
my bad ,just lucky enough not to have exploded something right

ok another question anything i can use to run the same pump with the same battery using a way to supply reduced current to the pump
thank you very much for the help and let me know if u wanna know something

Jul 18, 2013
10,872
2,528
Yes, did you look at the way I suggested?
You did not confirm as to how the inputs and outputs of the pump are configured or used, Did this pump and motor come as one unit? Or did you fit them together yourself?
Max.

7. ### suyash Thread Starter New Member

Jan 11, 2015
8
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the input is radially inwards and output is axially outwards with the input output holes of4mm dis each this did come as a set i did not fit them together
could u elaborate on the way u suggested i didn't quite get it
thanks a lot

Jul 18, 2013
10,872
2,528
If you restrict the output (discharge side) of a impeller pump it decreases the load and lowers the current, you can close off the discharge side completely for minimum current and see if it still draws excess current, if so, either you are running too high a voltage or the motor is miss-matched to the pump.
Max.

9. ### suyash Thread Starter New Member

Jan 11, 2015
8
0
thanks a heap ill try that now