30 replies to this topic

[Highnoon]

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.

[Eddie Fleming]

Could you have it set to control the amp draw rather than the voltage?

[Highnoon]

Set to voltage

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[Jesse Gonzales]

Happy Birthday Gary!

 

Jess Gonzales

[dalek]

The Gophert supplies control to either voltage OR amperage -- whichever gets to the limit you have set.  If the CC light comes on, the unit is controlling to the amperage limit you have set.

 

The sole purpose of the switch is to allow you to set limits.  In other words, you aren't telling the unit to control to voltage just because you have the switch in the V position.

You put the switch in the V position to set the maximum voltage limit you desire.

You put the switch in the A position to set the maximum amperage limit you desire.

 

[Highnoon]

Ok so I set volt at 5, whey is it going over? 

[MSwiss]

Gary,
You bought a $30 power supply and you are hoping for reliability and perfection?

There are plenty of good ones for $60-$80.

[gotboostedvr6]

I have your solution. Make offer!

[dalek]

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.

 

If I understand your main concern correctly, you set the voltage at 5 volts but you sometimes see the voltage start going higher.and then you quickly turn it off.

 

If I were you, as a test I would put the switch in the A position and set the amps limit to 5.00 amps.  Based on my experience, the fk motors can handle 5 amps for several seconds without causing damage.

Then put the switch in the V position and set it to 2.00 volts.

Then hook up a motor that is giving you the problem, turn on the power supply and look at how many amps the motor is drawing.  Begin increasing the voltage and keep observing the amps draw. 

When you get to 5 volts on your adjustment, see if the voltage increases on its own past say 6 volts (5.2 or 5.3 volts that you mentioned you were seeing, wouldn't be much of a concern to me.  I have the same power supply that you do). 

Also, watch the amperage and if it climbs past 5 amps (the limit you have set) then it looks like the power supply is defective.

 

If you're uneasy about setting the amps limit to 5, then try 3 or 4 amps instead just to see how things go.

[Highnoon]

Gary,
You bought a $30 power supply and you are hoping for reliability and perfection?

There are plenty of good ones for $60-$80.

just want to know if it is defective or is it a high draw motor issue, if defective I’ll buy another. What do you recommend for 60-80?

[Highnoon]

Happy Birthday Gary!

 

Jess Gonzales

Thanks.

[Highnoon]

 

If I understand your main concern correctly, you set the voltage at 5 volts but you sometimes see the voltage start going higher.and then you quickly turn it off.

 

If I were you, as a test I would put the switch in the A position and set the amps limit to 5.00 amps.  Based on my experience, the fk motors can handle 5 amps for several seconds without causing damage.

Then put the switch in the V position and set it to 2.00 volts.

Then hook up a motor that is giving you the problem, turn on the power supply and look at how many amps the motor is drawing.  Begin increasing the voltage and keep observing the amps draw. 

When you get to 5 volts on your adjustment, see if the voltage increases on its own past say 6 volts (5.2 or 5.3 volts that you mentioned you were seeing, wouldn't be much of a concern to me.  I have the same power supply that you do). 

Also, watch the amperage and if it climbs past 5 amps (the limit you have set) then it looks like the power supply is defective.

 

If you're uneasy about setting the amps limit to 5, then try 3 or 4 amps instead just to see how things go.

I set amp limit to 5, 2 was ok, 3 was ok, 4 was ok, at 5 it started again got up to 5.25 then would spike up to 5.55 then go back down so I shut it off. Amp draw was very high at 3.5.  Tried bunch of motors no problem, tried a 16d that was drawing 1.6 amps and when I got to 5 it when up to 5.15 and stayed there.

 

so got out an old slick 7 power supply with analog amp/volt meter and set the output to 12 volts via volt meter tester, since it has a rotary volt switch, connected my old trinity horsepower machine.  Tried 2,3,4,5 volts and no issue. In fact amp draw was 2.5 Which is still high, going to look at brushes.
 

so I think it is semi defective unit. 
 

thanks everyone for the help

[MSwiss]

just want to know if it is defective or is it a high draw motor issue, if defective I’ll buy another. What do you recommend for 60-80?

It's obviously not functioning correctly anymore.
PM sent.

[Mike Patterson]

I would just use the Slick 7 unit you mentioned. Pretty sure its better than any Chinese crap.

[Fred Zufelt]

I would set the Amperage to the MAX, the power supply will only put out what the motor requires/draws to run just like the virtually unlimited current when you run at the track..

 

The voltage is the governing setting.

 

The motor will not blow until over 13 volts as that is what we run on the tracks. 5 to 6 volt variance will not harm the motor.

 

The regulator may be going in the power supply, hard to fix

OR 

It may also be a dirty  Potentiometer.( the knob) It would not hurt to pull the top off the supply and spray the voltage pot with cleaner.

 

Nothing to loose.

 

Fred Z

[MSwiss]

Fred,
We run on (approx.) 13 volts, on the track, with a load.

I doubt the motor would survive very long, free revving, on 13V.

[Fred Zufelt]

Fred,
We run on (approx.) 13 volts, on the track, with a load.

I doubt the motor would survive very long, free revving, on 13V.

 

Yes you are correct. 

it would survive voltages until 13 volts and could be shut off. I was just pointing out that 5.5 volts would not kill the motor while testing the supply also use a motor you don't care about in case the powersuplly goes off the deep end.

 

Fred Z

[dalek]

Fred,
We run on (approx.) 13 volts, on the track, with a load.

I doubt the motor would survive very long, free revving, on 13V.

 

I was just curious, so I pulled a Hawk 7 out of my used-motors box, oiled the bushings, put it on my power supply at 13.1 volts and started my stopwatch.  That was an hour and 4 minutes ago and the motor sounds the same as it did when I started (like a little siren), it's still pulling .73 to .75 amps, and it isn't hot (I can easily hold it between my fingers).  I'm going to shut it off -- I'm tired of listening to it.

[MSwiss]

A Hawk 7 is a different motor than a 4002FK.

 

The tiny brushes are a choke of sorts, along with less overlap.

 

IOW, it is running more efficiently at the comm.

 

That's why there is never push-start issues.

 

And notice I used the word "doubt".

 

Try it with a 4002FK, and report back with the results.

 

Maybe it will live.

 

My point was that running a motor at 13.1 V at/on the track, is a lot different than free revving a motor at 13.1V.

 

[Fred Zufelt]

 

I was just curious, so I pulled a Hawk 7 out of my used-motors box, oiled the bushings, put it on my power supply at 13.1 volts and started my stopwatch.  That was an hour and 4 minutes ago and the motor sounds the same as it did when I started (like a little siren), it's still pulling .73 to .75 amps, and it isn't hot (I can easily hold it between my fingers).  I'm going to shut it off -- I'm tired of listening to it.

 

HAHA, I have blipped 12volts  or so once in a while to impress the neighbors but never for that long.

 

Good to know

Fred Z

[Fred Zufelt]

I was into winding.back in the day in the early 70s, 

 

As I reved the newly wound motor to full, the motor's commutator blew in my hand cutting it pretty bad.never did that again.

 

The comms are a lot better now and the wires are glued and tied, so there shouldn't be too much problems. 

 

They would draw less current than on the track as it is un loaded.

 

With that said it is not recommended to run your motor at full un-loaded.

 

Fred Z

[zipper]

In 70s I was testing my Pooch arms with a car battery charger, probably about 14V. Those that could stand it were good. Well, some did not - I did wear glasses...

[Bill from NH]

zipper, that's how I got my green arms hot enough to throw them out of balance, also during the early 70's. I never had one blow when doing this. By the mid-70's, I had built a Heathkit power supply as a replacement.

[dalek]

A Hawk 7 is a different motor than a 4002FK.

 

The tiny brushes are a choke of sorts, along with less overlap.

 

IOW, it is running more efficiently at the comm.

 

That's why there is never push-start issues.

 

And notice I used the word "doubt".

 

Try it with a 4002FK, and report back with the results.

 

Maybe it will live.

 

My point was that running a motor at 13.1 V at/on the track, is a lot different than free revving a motor at 13.1V.

 

 

I tried 3 of my PS4002FK motors at 13.2 volts.

2 of them settled in at about 1.4 amps.  Within about a minute I could only hold the cans for about 5 seconds.  After 5 minutes, the amperage and temperatures hadn't changed (I could still hold the cans for about 5 seconds).

The 3rd motor settled in at about 2.25 amps.  I could only hold the can for about 3 seconds but, like the others, the speed, amps and temperature remained stable.

I stopped at 5 minutes on each of them because they were stable and I assume would run like they were until the bushings needed oil.

[MSwiss]

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.