Speed Controller

[Tom O]

I finally received the speed controller from Amazon/ China for a Craftex 90 volt motor for a 2 x 72 grinder I want to build and as usual no wiring literature. It is 110 volts Input power as indicated and the motor connection are shown but the pulse width I have no idea about any idea? Well I just found out it’s not pulse width it’s for a stop switch!

 

[Johnwa]

According to youtube that’s for an emergency shut down switch

 

[Janger]

Looks like PW is a switch? perhaps for a safety switch?

 

[Janger]

post the link Tom to the page where you bought this?

 

[Tom O]

Here’s the link they come in 110 or 220.

https://www.amazon.ca/dp/B076KPP92X/ref=cm_sw_em_r_mt_dp_GsEmFbKZRM5TA

 

[Janger]

A reviewer commented:
Dangerous product, do not buy!
Reviewed in Canada on August 23, 2019
Verified Purchase
Motor outputs are phase chopped live mains AC not DC and will short to any path to ground, including you!!

Can anyone interpret the relevance of that?

 

[Brent H]

From the back of the unit it appears "it should" be an AC to DC speed control - as in, 110 V AC in and some DC voltage out? The Motor outputs being phase chopped live mains AC I believe that it is basically a speed control by stopping to the output at a certain point in the phase and then starting it up again to sort of "pulse" the motor. It is like using a Thyrisistor to only fire or allow voltage to pass at a certain point - you can use them to rectify circuits or for starting large motors. I think the person is saying that there is no ground provided that goes to the box and then on to your motor so if you make contact the thing will shock you during operation

 

[Brent H]

here is from the internet: https://en.wikipedia.org/wiki/Phase-fired_controller

 

[YYCHM]

Maybe just ground the housing assuming it's metal? You would think if it was allowed into the country it would have to meet some sort of CSA safety standard?

What if there is no ground wire?

If there is no equipment grounding conductor then replace with a nongrounding-type receptacle or a GFCI type that is marked "No Equipment Ground," or a grounding type if it is protected by a GFCI and marked "GFCI Protected" and marked "No Equipment Ground.

I guess it's the same issue as that shaver outlet in your bathroom. Need to use a GFCI protected circuit.

 

[Johnwa]

if it’s simply a thyristor bridge rectifier then both of motor out connections will be live. If either of the motor is Internally grounded then the motor case will become energized.

 

[YYCHM]

if it’s simply a thyristor bridge rectifier then both of motor out connections will be live. If either of the motor is Internally grounded then the motor case will become energized.

And in layman's term means what? Is this thing a hazard or not?

 

[Johnwa]

If neither of the motor leads is connected to ground then it should be fine. An ohmmeter check between the motor leads and the case would confirm that.

 

[YYCHM]

If neither of the motor leads is connected to ground then it should be fine. An ohmmeter check between the motor leads and the case would confirm that.

Does he need a GFCI circuit on the AC side?

Craig

 

[Johnwa]

A GFI isn’t required but a ground from the motor case to the receptacle ground is a good idea.

 

[Tom O]

Well I will check it out in a week or so the push is on to finish up the tiling in the bathroom because on Friday it’s slice and dice to remove a 28 mm kidney stone.

 

[Janger]

That's a boulder! Best wishes Tom hope that is uneventful for you and an easy recovery. Keep that stone eh?

 

[Dabbler]

28 mm kidney stone

wow

 

[Brent H]

Holy smokes Tom!!!

I had a 7.3 mm and thought I was on the way out! get that sucker in a jar and after recovery machine it into a statue or something! good luck and I hope all goes great for you Friday!!!

 

[YYCHM]

All the best Tom!!!

 

[Tom O]

Well this is the third go at stones first they blasted one then just sandblast the porcelain but I was always wondering about if it doesn’t all come out does it create more stones by supplying more left over material, the second went up the pipe leaving stents to be pulled out at home! So this time might be the best because I can’t picture any problems beside some healing. Then it’s a reshedualing ( Covid ) for gallstones that they think caused my stint in the Rockeyview last March.