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 230V build, a lot of Amps one phase... 
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Joined: Wed Dec 21, 2016 8:14 am
Posts: 3

Just started to source some fans but my question is how do I use more than 3 motors without blowing the fuse on the single phase?
Here in Sweden it's hard to get more then 16Amps, there are usually 32Amps available but not always.


Wed Jan 17, 2018 4:08 pm

Joined: Wed Mar 03, 2010 3:40 pm
Posts: 1287
Location: Melbourne, Australia
Its really difficult.... and the available power is what eventually limits most of us.

First thing is to use phase control to control the speed of all your motors together. That will also offer the very big advantage of a soft startup.
The motors will then accelerate very gently over a few seconds up to the final selected speed. There is no massive fuse blowing or circuit breaker popping power surge that you would get from a very abrupt direct full power switch on.
Motor switching is not a good idea, full speed control of all motors together is much more gentle when you are working right up near the power limit.

Next thing is to fit an amp meter to your bench. You will very quickly learn from experience how far you can "wind up the wick" before the circuit breaker pops. Its entirely reasonable to fit an extra motor or two so that you can tweak up to full power and still have a bit of speed adjustment remaining. The motors will probably last longer too if they are run at slightly less than full flat out.

It may be possible to get a 30 amp feed run from your fusebox to where the flowbench is. That is pretty much the maximum single phase current possible from one single power outlet, at least here in Australia.

Beyond that you might consider getting a second or a third phase run from the street, although that can get expensive.

Don't tell them its for your workshop or garage, they will think you are setting up factory in a domestic area.
Say its for a huge spa or a sauna. That would be more believable in your climate than a lot of airconditioning which is the excuse I used, haha.

Only other alternative, although its a bit extreme, would be to run your bench from a suitably sized standby power generator .

Also known as the infamous "Warpspeed" on some other Forums.

Fri Jan 19, 2018 6:37 pm

Joined: Thu Feb 25, 2010 3:39 pm
Posts: 715
I just bought one of these for my bench. Might help you keep an eye on your amp flow.


Sun Jan 21, 2018 2:43 pm

Joined: Thu Mar 31, 2011 10:52 am
Posts: 32
There's no solution to this.

You can seek for the most efficient blower but you won't have massive gain.

I built my flowbench a few years back and started with 2 blower + phase control. I then added 2 blower and started having amp issue (was on 16A max).
Keep in mind the blower might not be very efficient when the spin slowly so you better have 2 spining fast than 4 slowly => if 2 big blower max-out you amperage capacity don't fit 4.

Now I have 8 blowers and 32A feed. It's fine but in the near future I'll use two phases for added security.

Sun Jan 28, 2018 5:37 am
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