Minarik Variable Speed Control

Jim Smyth

Jim Smyth

Joined
Oct 4, 1998
Messages
696
I purchassed a Wilton Square Wheel Grinder with a Leeson DC Motor with a Minarik Variable Speed Control from Koval at the 1999 Blade show.

Since the purchase I have sent the Minarik control back to them 3 separate times because it would blow one of the two 15 amp circuit breakers inside the box. I would receive it back and was told they couldnt find anything wrong. That was in the fist month of owning it.

I have occasionaly had to replace a breaker when I worked it to hard for too long but that was like every 6-8 months since the intial time frame. Yesterday the breaker smoked again so I let it cool (unit has a heat sink on it)and replaced the breaker and it smoked again. Went thru 5 breakers yesterday and couldnt get it to work again. As soon as the main breaker is turned back on and the power is turned on the Wilton it smokes the internal breaker.

Question, has anyone else had problems with this variable speed unit? It seems the on/off switch is real hard to move one and off but I am somewhat reluctant to invest any more money in parts and am considering buying a new variable speed unit from a different manufacturor.

Any recommendations on a variable speed unit? Thanks in advance.
 
I have been using Leeson VS motors and Minarik controls since 1992, the same one's. I have never had a problem. I sounds like you definately have something wrong.
You said you sent it back, I am assuming you meant, to Minarik, and not Koval.
You might want to call someone, at Minarik, and really go over this with them on the phone. :confused:
Just happened to think. Is there anyway that steel dust could be getting inside? Could be a short caused by dust buildup.
A lot of people(myself included)bought the controls in NEMA1 enclosures,=not dust tight, or watertight, to save $$. I sealed my cans with silicone, but I am still very careful to keep them as clean as I can. Just a thought. Good luck.
 
Mike, I happen to live near Minarik where they are distributed, they are like a 30 minute drive. In the beginning I did talk to Mick alot about this problem and decided to drive rather than go thru him since it was close. The 3 times I ended up driveing there and going into there shop. They would put it on a test bench and got it to work each time. Thats when he talked me into a heat sink for it which seemed to help. But the problem really never did go away. I assume metal dust could get into the unit, I am not familair with the term Nema enclosers? Is this just the houseing? Also you said you sealed you cans with silicone? Is this the adjustment pods inside? Thanks for the help.
 
Jim,

I'm guessing that you are using the 1.5hp motor and running it on 110V.....?

If this is the case, then you are really pushing the current rating for the controller, and your residential outlet.


I looked into this problem a few months ago only to learn that they (some controller manufacturers) will rate the controller at 1.5hp.. however it is really a stretch to maintain that output for periods.

The other problem is that 1.5hp it right on the edge of max current for most 110V outlets. I'm thinking that your outlet breaker is 15A...which is near the current drawn from 1.5 hp at 110V....this problem may be aggrivated if you are using anything else on this circuit such as lights, radio, fan...etc

If this senerio describes your setup, a solution is to swith it over to 220V input. Then the current drops in half and everything runs cooler. No more headaches and maybe a cost savings in the long run.

These are just some off-the cuff thoughts.

I hope it helps,
Sincerely,
Rob
 
Rob, Its a 1HP motor on 110V. I wired my shop with all the machines plugged into the same 15 amp circuit. I only use 1 machine at a time. The only exception is I have a small radio plugged into the circuit so I know for sure if the power is on or off when I am working. All the lites and vac system are on other circuits. When I am not in or using the shop I trip the main breaker for the machines so my kids won't get hurt when I'm out of town if they accidently turn something on. I can only assume that this controller is the correct one since Mick sells them as a package.
 
Jim, NEMA=national electrical manufacturers assoc. It is an industry wide set of standards.
I was just referring to the enclosures, I ran a bead of silicone around the seams, and toggle switches, where dust might get in.
You may already have a dust tight enclosure. If you are in doubt, get the part number of the control unit and call Minarik. They can tell you.
Mine are all running on 220/240V, and I did not even think of voltage as the problem. What Rob said could very well be it.
Was typing while you were posting. I guess that answers the voltage problem.
You might want to talk to management at Minarik and explain whats going on. They are usually pretty good about handling problems.
If it is intermittant, the repair guys at Minarik won't spot it, and don't have the time to make it happen.
 
Jim, I was talking to a friend who had just read this thread(Mike Fitzgerald, Fitzo), he brought up something I had not thought of. Is it possible that the cord from your control to the "wall" receptacle is too small a gauge? Could you maybe be running an extension cord, from the wall receptacle, which your control is plugged into. Anything like that, with too small a wire size will cause too much resistance, and blow fuses. Just a thought. :confused:
 
Mike, appreciate the effort. The cord I am using is the one that comes in the wiring kit. It is heavy duty. Best I can tell is that I may have got a lemon and may try another unit on Monday when they open. I do like the silicone idea but with how often it blew the internal breaker wouldn't be a good idea. Maybe if the new unit works better I will do that for sure.
 
I did my trade as an electrician, in Australia we only have 240v.
But there are a few common threads to all motors.

At start up they draw 6 time the full load current while the motor ramps up.

All have a duty cycle. I.e some rated continus use some need to be cooled after a running time set by the maker.

As load is increased amps goes up. if you give a good portion of shoulder to the job, amps up.

A trap can sometimes be using a flat plattern. The friction between the back of the belt and the plattern can increase the load. A mate with a 1/2 horse power motor uses a bit of graphite when he uses the platten to flatten the billet length wise. Stops his cutting out on
overload.

If your controller is electronic a problem can easilly occour as the have sujested with dust shorting. A number of components require a heat sink to keep cool. often all that is used to insulate from cassing of component to frame is a thin layer of paste and a thin sheet of high temerature insulation. Very easy to short some times hard to pick up on a test bench.

Good luck
 
Well, I bit the bullet and went and bought another variable speed unit from Minarik today. Got the same exact one since I suspected it was the problem from the beginning. The new one works great! It also starts nice and smooth where the old one used to sort of jerk when turned on. Guess it wasnt right from the beginning. I am sending the old one in and will get a quote for repair and will then have a spare for future replacment or another machine. Thanks again for all the good sugestions and help.
 
Jim, you're welcome, and glad it worked out OK. :D
BTW, in the instructions, they tell you how to adjust the controller if your motor jerks, etc. Good luck.
 
Mike, the controller I got from Mick and also from Minarik didnt have any instructions that were included in the box. I guess if I asked them ay Minarik they could of found some. Mick included a photo copied sheet that was almost impossible to read on how to set up the pots inside the variable speed when I purchased it in 1999. I set the new one up the same as the old one and used it all day yesterday without a hitch. The guy at Ace Hardware isnt going to like it since I bought all his 15 amp slow blow fuses he always had in stock! ;) The folks at Minarik were real helpfull and gave me a great price on the unit and remembered me from 1999 when I was in there the 3 times. Nice to have equipment that works as advertised. :)
 
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