30 replies to this topic

[Fred Zufelt]

I have a gophert power supply, been working well for about a year. Only use it for motors, no tire truing

 

mostly use it for fk motors, I break in at 2 volts then 3 volts and then put it on 5 for a short amount of time. Recently on some motors, higher draw, the voltage will start climbing and bouncing around like goes from 5 and starts climbing like 5.2,5.3, etc, keeps going up and I turn it off quickly. It doesn’t do that at on 2 or 3 but it does hunt around like 1.98-202 and 2.98-3.02 ish.

 

Any ideas, I googled got nothing related to this issue.

 

thanks for your help.

Highnoon,

 

in case it got  lost in all this blown motor chat. Nothing cooler than a smoken motor doing laps unless it's yours LOL

 

Try cleaning the voltage pot with contact cleaner, un plug, take off the cover and spray the pot.

 

This may bring it back to stability.

 

Good luck

Fred Z

[dalek]

Congrats.

I still don't see Gary, and anyone else,wanting to risk throwing a wind or a lam, on a good motor, exposing it to conditions it won't see in a race, unless it spins a pinion.

And as a raceway owner, I don't see any benefit in encouraging practices that could hurt a racer.

Along with what Fred mentioned, I've seen someone cut above the eye with a blown lam, and I've been hit in the chest with one of the 3 segments of a blown comm.

When I picked up the offending car, which had free wheeled through the Bank, I could see the bare armature shaft.

The comm was completely gone.

 

Good points, Mike.

 

But remember, in one of your posts you said "Try it with a 4002FK, and report back with the results" so it's your fault I did what I did. LOL

 

In post #1, the OP seemed worried that a motor might be damaged when free-revved at 5.3 volts because he said he "turned it off quickly".

 

The reason I did what I did was to show him (and myself) that he had nothing to worry about at 5.3 volts, meaning that he could let the voltage run on up much higher that 5.3 without risk to himself or the motor.  This would allow him to test his power supply more thoroughly, which he was troubleshooting.

 

I have the package that a Hawk Retro came in and on the back it says the recommended voltage is 12 - 12.5.  IOW, it's a 12.5 volt motor that I ran at 13 volts (not much higher than "recommended" and I figure the engineers designed in some wiggle room).  It's a 12.5v motor that might see as much as 14v in an automotive application and with no "minimum load" spec that I've ever seen on any motor package.

 

The bottom line is, I believe what I did was very low-risk and it demonstrated to the OP what I intended.

 

[MSwiss]

Agreed, Gary certainly didn't have anything to worry about, with the motor creeping up a few .1's higher than 5V.

About 7 years ago, I ran a Retro Hawk at 28V.(under an overturned tupperware container).

It didn't blow.

I don't remember if it ever went back in a car.

I got in an Ebay power supply for a local racer, that was defective, where the voltage would surge up.

It blew up a couple 4002FK's, before I sent it back for a refund.

But that was quite a bit higher than 13V.

[Fred Zufelt]

it seems you guys have come to terms. Stop you are both right LOL

 

Mike Swiss what track do you own, always looking for  a new check mark in my book. No home track here so every race is a major trip. this OK because I'm retired LOL

 

The bottom line I would like to know if a dirty pot is the power supply problem ?

 

Any word Highnoon

Fred Z

[MSwiss]

Chicagoland Raceway.

If a dirty pot was the issue,
would the problem only crop up, with certain motors, and at a certain/higher voltage.

Is the inside of the pot even easily accessible, to try cleaning?

IOW, is it sealed, like a DiFalco economy brake pot?

[Fred Zufelt]

The pot is hooked up to a chip that controls the voltage and the current depending on where the switch is.

 

If the chip ( or CPU ) is bad you probably wouldn't get any voltage, or may not control it very much.

 

It seems to me to be working only giving out a poor regulated output

 

Yes it it probably semi sealed but there will be holes that a small amount of cleaner can get into.

work the pot back and forth and hopefully it will clean up.

 

it the pot is dirty the Ohms can go all over the place causing a very erratic effect on the voltage. 

 

If he is going to through it out  anyway to me it is worth a try.

 

I hope to get to the Chicago area next summer there seems to be a lot of tracks there.

 

It seems Highnoon is  not following this thread anymore

 

Fred Z