Bought a motor speed controller today...

[RaceDiagnostics]

...for my Makita rotary polisher. Its an old one that either goes fast or faster. I though it would be good to have some more fine control.

This one cost me 1pence, plus £9 shipping from China.

https://www.ebay.co.uk/itm/253478495813?ViewItem=&item=253478495813

Seems crazy that they are actually making their money on the inflated shipping cost.

 

[ukracer]

...for my Makita rotary polisher. Its an old one that either goes fast or faster. I though it would be good to have some more fine control.

This one cost me 1pence, plus £9 shipping from China.

https://www.ebay.co.uk/itm/253478495813?ViewItem=&item=253478495813

Seems crazy that they are actually making their money on the inflated shipping cost.

And totally destroy the chance of us competing.......

 

[Kram]

Likely to melt or catch fire, use 240v speed controllers with caution.

 

[RaceDiagnostics]

Likely to melt or catch fire, use 240v speed controllers with caution.

What evidence do you have for this, my drill, angle grinder and power file all have 240v speed controllers on them, none of which have caught fire.

Did you simply ignore the positive feedback reviews?

 

[zx9]

What evidence do you have for this, my drill, angle grinder and power file all have 240v speed controllers on them, none of which have caught fire.

Did you simply ignore the positive feedback reviews?

I hope you do a follow up post when it arrives, I have been looking at similar product but not hit the button yet.

 

[RaceDiagnostics]

I received my 1 pence motor speed controller today and gave it a test, so 10 days for delivery from China.

The unit fees fairly sturdy superficially and works as expected. It uses a ST Microelectronics 40AMP traic for the control which is good.

Here is a quick video on it.

However it does have a few faults.

No rubber feet on the case.
The cable strain relief is just a grommet, so no strain relief at all and if say tripped over may rip out completely.
The pcb is mounted uncomfortably close/touching the metal case without any insulation (other than the paint) between.
Its not fused.
And most importantly the case is not earthed.

So in summary, I would say that it is a great deal for 1pence. I will put it in a better case to overcome the issues above and will be happy to use it.

 

[angellonewolf]

only thing i would say is that unit you will have no earth ? if it 2 pin from china

 

[RaceDiagnostics]

Comes with an earthed plug/cable.

 

[angellonewolf]

missed that quick on the vid

 

[Bladevane]

Is this suitable for controlling the speed of an induction motor? I was looking at those today because I have discovered a Bonfiglioli 240v motor/reduction gearbox with output speed of 6.5 rpm and want to reduce this to make a welding manipulator.

 

[Seadog]

Is this suitable for controlling the speed of an induction motor?

No, you need a variable frequency to control an induction motor.

 

[Bladevane]

Thought so. Thanks.

 

[RaceDiagnostics]

The fan in the heater in the video must have been an induction motor and its speed did vary with the voltage, may be an odd ball motor type?

 

[rtbcomp]

You'll be delivering a chopped voltage to the motor so less power consequently lower torque, so it will slow down under load.