30 replies to this topic

[Mike Whitley]

Having a problem with my controllers overheating to the point they start smoking and burn the wires on the 15 ohm double resistors. The power supply is putting out 12.92 volts DC to the track. Is that too much? I am not even hooking up the red break wire. What am I doing wrong ?

[Justin A. Porter]

What variety of track? What variety of cars? And how much part-throttle running are you doing?

 

The truth is that any one of several things could lead to overheating controllers.

[Mike Whitley]

This is on my home track and we do a lot of variable speed driving.

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[Samiam]

15 ohms seems a bit high, even for a home track. If you use mostly part throttle and never full punch it, the resistor never has any time to cool off. Lower the power to 10.5v-11v.  Or just get a DiFalco with interchangeable resistor modules. 

[MSwiss]

Justin had good questions and all of what Sam said was good, including 15 ohms seeming to be on the high side.

 

What kind of motors are you using?

 

Are you able to adjust/lower your power?

 

If so, as low as you want?

 

If not, you might consider the below, that is infinite, down to zero;

 

http://www.mastechpo...protection.html

 

For controllers, you probably want something like a Koford M366-3 or M366-4.

 

The heat is distributed all through those blue resistance wires, not just in the handle.

 

When I was GM at Koford Eng., I talked my old boss, Stu Koford, into going to that design on our low end controllers, when we ran out of parts to make the handle contained resistors.

 

The looped resistance wires was something he had done on a personal controller of his, many years before, that I had remembered, and I thought was pretty slick.

 

I've used the M366-3 for rental controllers at my raceway, since I opened, in 2005.

 

PS-if you can't adjust the power down, and you're using something like 16D's or Super 16D's,try a low amp drawing motor like a JK Hawk MB.

 

Along with being able to drive the car harder with the slower motor, it's lower power draw will heat up the controller less, in the middle bands.

[Ramcatlarry]

Ohms Law applies. Volts times amps equals watts.  And 35 watts divided by 12 volts equals the maximum amperage the controller should use without overheating.  Single barrel resisters are about 25 watts and dual turbos are about 35 watts.  The old external long sticks are rated at 100 watts and most transistor brands like Difalco, Ruddick, or Third-Eye are well over 100 watts.

 

If the car does not move at 1/4 throttle, the ohm rating is too high for that motor....

[MSwiss]

Larry,

As usual someone asks what time it is, and you tell them how to make a clock.

 

The track configuration is the biggest deciding factor.

 

IOW, the amount of partial speed driving.

 

What might work on an oval that, is on-off, on-off, might not work on a twisty track like the above.

[gotboostedvr6]

That track is a beauty!

[MSwiss]

If the car does not move at 1/4 throttle, the ohm rating is too high for that motor....

Larry,

The above comment, you added, is a good one.

 

 

The Koford M366-3 described in the bottom quote;

 

 

For controllers, you probably want something like a Koford M366-3 or M366-4.
 
The heat is distributed all through those blue resistance wires, not just in the handle.

[Bill from NH]

Mike S., what's the purpose of the blue-wrapped wire? In the photo, it appears to end half way to the clips. Is it connected to one of the others at that point?  I've not seen these Koford controllers before.

[MSwiss]

Here's a close-up on the older model switch block, that shows it well.
 
It's thin, insulated wire, that is cut to length, and soldered from band to band, to create your resistance.
 
Each approx. 40" loop of wire is approx. 3/8ths of an ohm, so this 8 band controller is 3 ohms total.
 
And thus the heat from each band/"speed" is distributed along 40" of wire, instead of a loop around, a single or double ceramic barrel, all contained in the handle.
 

[Mike Patterson]

I had just started to write this when Mike Swiss posted the above. I was going to say, since no one had gotten specific, try a 3 ohm controller. I used one (a  Parma Turbo) for years! Get one and try it, then report back.

 

What kind of controllers are you using now? Since you mentioned they were 15 ohm, are the from the 1960s?

[Half Fast]

Mike - that is one helluva clever design

 

We could have used that back in the sixties instead of the hand heater resistor controllers we had back then.

 

Cheers

[Bill from NH]

Thanks Mike! The last post cleared things up.

[MSwiss]

Mike - that is one helluva clever design

 

We could have used that back in the sixties instead of the hand heater resistor controllers we had back then.

 

Cheers

Thanks.

 

We already had 1000's of the pictured circuit board/switch blocks, that were made for our external resistor controller.

 

So it became essentially an external resistor controller, without the expensive hanging 100 watt external resistor.

 

Stu finally ran out of them recently, hence the different looking one, in the complete controller pic.

 

Stu's personal controller, that inspired me, from the early to mid 80's, was really neat.

 

It was technically wiperless.

 

The resistance loops were connected to a series of spaced, suspended leafs.

 

As you pulled the trigger, you were just pressing one leaf, against another leaf, against another leaf, lowering the resistance each time, until you hit the "full on" stop.

[Mike Whitley]

Thanks for the comments guys. I might have bought some stuff that does not work.  First the controllers are used Parma Turbo ones I bought on ebay. Mark at Parma suggested the 15ohm because the 3ohm ones I bought were like off and wide open ( no variable speed) so I changed them all out to 15ohm. 

My power supply is not variable, it measures 12,92 volts DC on the track. I will check in to the Koford controller and also a variable volt power supply. Thanks. 

[MSwiss]

What kind of motors do you typically run?

 

PM sent.

[Racer36]

I would endorse the Koford controller that Mike suggested. I have been selling them to new club members for several years and they are excellent, and more robust than you might think.

[FSK]

Everyone has said the truth. The resister will heat up when using the middle of it, try to drive on off on off. [May not be able to do this on that beautiful track ]   the resister will not heat up. If you would like to try different ohm resisters I will send you a couple. SK

[Eddie Fleming]

In post #1 you said you were not even hooking up the red break wire.

 

This should have no effect on the controller heat problem you are having. You can run with or without the breaks bur the resistor is not used in breaking.

[Mike Whitley]

What kind of motors do you typically run?

 

PM sent.

 

What kind of motors do you typically run?

 

PM sent.

16D's

[MSwiss]

16D's aren't crazy.

 

Lowering the voltage is the main thing.

 

If that doesn't work, than you might try the JK Hawk MB.

 

FWIW, I run my rentals, with a slightly faster motor, at about 8V.

[Mike Whitley]

16D's aren't crazy.

 

Lowering the voltage is the main thing.

 

If that doesn't work, than you might try the JK Hawk MB.

 

FWIW, I run my rentals, with a slightly faster motor, at about 8V.

The converter I have is a Compact Power 1200 I bought on Amazon. It has plenty of power, 75 amps/90 watts @ 110 volts. I have looked at Voltage regulators on Amazon but there are so many and I know nothing about them. Any suggestions as to which one I should get to hook up to my converter and will that work?

[MSwiss]

I assume the voltage regulators you are looking at, are cheaper than the $289 price for an adjustable Mastech.

 

Regardless, I've never purchased one, so I hesitate to make a recommendation, and sort of be responsible, if it fails.

 

You should check with a tech from the company you intend to purchase it from.

[Dave Crevie]

FWIW; Back when I ran GP10 (16Ds), I used 15 ohm Parma Turbos. Looking at your track, I would do likewise. In

any event, nothing over 10 ohms.