mini saw speed controller 230v 480W 10,000 rpm

[rjsutton]

Hi i brought a mini table saw which came with a combination off-on-speed controller. when started the motor "pulses" it seems to reach speed then just drops off then starts up again. the faster the speed controlled the faster it pulses and dies.
10,000 rmp is over twice what i want to use a rpm
I tried a 500w fan -light dimmer but that let all the magic smoke out.
Can someone answer if a 500W ceiling fan speed controller work with this motor. ive already blown $25 for the dimmer and a 500w fan controller is $50.
or do i need a AC 220V 4000W SCR Voltage Regulator Dimmer Electronic Motor Speed Controller
specs
input voltage: AC 220V
Voltage regulation: AC 0-220V
Maximum power: 4000 W
Current: 25A
as in pic

appreciate any help
regards Richard

[m_c]

It depends on what kind of motor is fitted.

If it's an induction motor, then the only way to control speed is by altering the supply frequency, which you can't really do with a single phase motor.
If it's a DC brushed motor, then that SCR drive should work.

[A_Camera]

Surely there is something wrong with that "on-off speed controller". The way you describe it, is not normal, no motor speed controller should do that. Contact the seller and request a repair or refund. Is the saw OK if you run at full speed?

There is also no way of knowing that the dimmer you are showing is for inductive or resistive loads, and since it seems to be a cheap eBay version, I'd suspect it is NOT as you describe it, it can definitely not handle 4kW inductive load.

You say it is for a mini table saw, but how is the motor? What sort of brand and design is that? What are the motor specifications? I have a Proxxon mini saw with 85W motor, I don't even dream about reducing the rpm, because it would just stop. Also my large Bosch is always running at full speed, even though it has a 1.8kW motor. Why would you want to reduce the rpm? You know that by doing that, you also severely reduce the torque.

[rjsutton]

Hi
the supplier actually sent me replacement saw but it as well as his whole stock did the same weird pulsing. he refunded totally and told me to keep the 2 hes already sent
he cant (or cant be bothered repairing them) all brand new in boxes etc from Yes "china" from a tool sale shop in NZ
a 150mm tungsten blade running at 10,000 rpm is a very scary thing it scream and shakes the saw, far to fast
see pics of original speed controller
i am only cutting 5mm thick timber sheets so thats why i brought a mini saw. it will work fine if the speed pulse issue can go also specs of a local fan dimmer specs. would this work ( 500W)

[rjsutton]

see pic

[m_c]

That looks just like a pretty standard brushed motor, like you'd find on a router/drill (if you happen to have a broken router/drill, you could butcher the speed controller from them..)

I'm trying to remember if a basic PWM type speed controller will work with that.
Something tells me, the field windings still need full power, and you control speed through only regulating the armature power, but it's been that long since I've dealt with an AC brushed motor, I can't actually remember.

[rjsutton]

sorry details

[Clive S]

see pic

Are you sure that the blade is running at 10K or is it geared belted down for more toque.

Does that work out at 4800 Mtr per tooth !!

Googled 6-1/2″ 4500 – 8000 rpm SFM

[rjsutton]

Hi direct feed of motor armature. no gearbox motor speed listed as 10,000 rmp
thanks

[Doddy]

Complete guesswork here, but the pulsing may be from an overcurrent protection kicking in, given the initial "stall" current of the motor may be many times the rated operaing current of the motor. In which case you need either a dedicated motor-speed controller (rather than a light dimmer) or serious overrate the dimmer (factor 10x +)

[A_Camera]

Hi
the supplier actually sent me replacement saw but it as well as his whole stock did the same weird pulsing. he refunded totally and told me to keep the 2 hes already sent
he cant (or cant be bothered repairing them) all brand new in boxes etc from Yes "china" from a tool sale shop in NZ
a 150mm tungsten blade running at 10,000 rpm is a very scary thing it scream and shakes the saw, far to fast
see pics of original speed controller

I agree, you should be careful which blades you are using. I only use quality blades, some of them are good for 12,000 rpm, but some are not even good for 7000 rpm. Never the less, a circular saw always looks scary when it is your firs one, and of course, they are very dangerous. Even my tiny can chop off a finger since even that one manages to cut 5mm aluminium sheets.


i am only cutting 5mm thick timber sheets so thats why i brought a mini saw. it will work fine if the speed pulse issue can go also specs of a local fan dimmer specs. would this work ( 500W)

To be honest, I'd bite the bullet and buy another, better saw. Experimenting with the rpm using similar regulators maybe feels good for your wallet, but I think it's waste of time and money. Especially if all you need it for is a few mm wood then even this one would do: https://www.proxxon.com/en/micromot/27006.php or if you need larger then this https://www.proxxon.com/en/micromot/27070.php. Of course, there might be other table saw also which might be good for your use, but it sounds like the one you bought is really poor quality, especially since the blade is directly driven. My tiny KS 230 has a gearbox in it, reducing the rpm to about 4800 rpm and increasing the torque by about 40%, which is why that small 85W motor can cut aluminium, PCB and other non-ferrous metal, but not with the delivered blade, I bought special blades for the purpose.

Regarding that dimmer, it is probably made for 500W resistive load, not the same as 500W inductive, which a motor is. Also, as I said before, reducing the rpm through voltage reduction means reducing the torque, so I think that's generally a bad idea.