Low power low flow rate high temp. pump

[chris w]

Hi there,dont know if you are still looking but maplins sell a couple of PWM motor speed controllers for £15. Designed for 12v nominal input , 3A output. May give you further options to reduce speed and power consumption, hth, Dave

 

 

If it's a standard water pump, the Maplin circuit won't handle the current. You could modify ithe circuit by changing the MOSFET output transistor to something like an IRF540 which will handle the current with no problem.

 

Chris

[Keeping Up]

I have assumed a 20W bulb and a "normal" water pump (ie: 12v 8A)

 

If it's a standard water pump, the Maplin circuit won't handle the current. You could modify ithe circuit by changing the MOSFET output transistor to something like an IRF540 which will handle the current with no problem.

 

Are you still assuming it's a big (8A) pump? The OP was about a central-heating type Jabsco pump which consumes 1.3A

 

I've once run one of these Jabsco's off as little as 3v quite successfully, and the idea discussed earlier about a light-bulb in series is also perfectly feasible (the initial current surge in the cold bulb even helps to kick-start it) and a cheap option to try first - or have I missed something in my quick reading of the thread?

 

Allan

[tomandsophie]

oh, a bypass, that's a good idea.

 

don't say I didn't recommend that abot 2 weeks ago ..............................

 

Sorry Chris, too much information all at once. I've just finished installing it, so now I've just got to try it out...

[John Orentas]

I am not surprised that one or two people are getting a bit frustrated here. Tom you have had several very well reasoned replies to your very extensive number of posts, I and probably others get the impression that you do not read them and you certainly recognise very few.

 

One example only, I suggested that you use a chopped dc controller what feels like weeks ago, that would certainly have done the job as would the bypass system that is now being suggested by others. I cautioned against the use of series resistors a long time ago, now you seem to be considering that path again.

 

What is all this about shower pumps, you started off talking about circulating pumps.

 

There are many people on the forum who can help you with your problems but you really should try to respond correctly.

[tomandsophie]

I am not surprised that one or two people are getting a bit frustrated here. Tom you have had several very well reasoned replies to your very extensive number of posts, I and probably others get the impression that you do not read them and you certainly recognise very few.

 

One example only, I suggested that you use a chopped dc controller what feels like weeks ago, that would certainly have done the job as would the bypass system that is now being suggested by others. I cautioned against the use of series resistors a long time ago, now you seem to be considering that path again.

 

What is all this about shower pumps, you started off talking about circulating pumps.

 

There are many people on the forum who can help you with your problems but you really should try to respond correctly.

 

As should you John. I have not at any point mentioned anything about shower pumps - I really don't know what you're talking about on that one. I haven't said a word about considering the path of using series resistors either. I suggest that you read the posts properly too and also notice that I have been very careful to say how grateful I am for everybody's help.

I suggest that you don't say what doesn't need to be said and let the rest of us happily exchange friendly information.