pump head doubler?

[Peter Fairbrother]

I have a small aquarium pump and I want to increase the head.

It is mains (50 Hz, UK) operated, and I thought if I doubled the
frequency it would, ignoring losses, double the head.

It uses 6 watts maximum, but the power needed here would be considerably
less than 1 watt, as the flow will be small - also it is submerged, so I
do not anticipate any overheating problems.


To obtain a doubled frequency I thought of using a diode full-wave
bridge with a capacitor in series with the pump. Would this work?

If so, how would I calculate the value for the capacitor?

Class Y?


(suggestions about alternative pumps welcome - if they are quiet, 230V
mains operated submersible, cost less than £5 delivered, and have a 2m
plus head)

Thanks,

-- Peter Fairbrother

 

[whit3rd]

I have a small aquarium pump and I want to increase the head.



It is mains (50 Hz, UK) operated, and I thought if I doubled the
frequency it would, ignoring losses, double the head.

[and full-wave rectifier with AC coupling is described as
frequency doubler]

If it's a shaded-pole motor, that would possibly work, but could
also stall the motor. Your 240V 50 Hz has peak-peak voltage
of 678 volts; the full-wave rectifier has 100 Hz, but at peak-peak
voltage of 339V.
Losses are not necessarily negligible.
Easier, would be to use two pumps in series (pump 1 to a holding tank
containing pump 2, if they're immersibles).
If the pump is dismountable from the motor, belt-drive will allow
speed change. So-called polycord belting is easy to work with.

 

[Jasen Betts]

I have a small aquarium pump and I want to increase the head.

It is mains (50 Hz, UK) operated, and I thought if I doubled the
frequency it would, ignoring losses, double the head.

or you might get cavitation detonate the motor or destroy the propeller,
consumer devices are engineered to within a hair's breadth of failure
to save tiny amounts per unit.

It uses 6 watts maximum, but the power needed here would be considerably
less than 1 watt, as the flow will be small - also it is submerged, so I
do not anticipate any overheating problems.

To obtain a doubled frequency I thought of using a diode full-wave
bridge with a capacitor in series with the pump. Would this work?

The voltage will be wrong,

can you plumb two similar pumps in series so that the output from the
first goes into second. that shopuld give double the head.

 

[George Herold]

I have a small aquarium pump and I want to increase the head.

It is mains (50 Hz, UK) operated, and I thought if I doubled the
frequency it would, ignoring losses, double the head.

It uses 6 watts maximum, but the power needed here would be considerably
less than 1 watt, as the flow will be small - also it is submerged, so I
do not anticipate any overheating problems.

To obtain a doubled frequency I thought of using a diode full-wave
bridge with a capacitor in series with the pump. Would this work?

If so, how would I calculate the value for the capacitor?

Class Y?

(suggestions about alternative pumps welcome - if they are quiet, 230V
mains operated submersible, cost less than £5 delivered, and have a 2m
plus head)

I'm assuming a water pump. (and not an air pump.)
What type of motor? permanent magnet?
It seems unlikely to work, but maybe fun to try. (you may wreck the motor.)

2m head at what flow rate? The price you want looks to be very low.
(I made some different 'weird' pumps in my mis-spent youth. There was a reverse water wheel, and an Archimedes screw pump.... neither with that big of a head.)

George H.