Kent TR36 Golf cart charger

[Caleb]

Hi guys, was trying to get this back up and running for a friend. There appears to be some sort of relay that is blown apart, on one leg of the red wires is 128vac, on the black wire is 1.8vac the second red wire has no voltage, both red wires tie into a timer to set hours for charging. Any ideas what the burnt to a crisp part might be?

[stj]

Re: Kent TR36 Golf cart charger

what's stamped on the metal?

[budm]

Re: Kent TR36 Golf cart charger

Pictures that show the whole unit? Any power transformer?

[Caleb]

Re: Kent TR36 Golf cart charger

@ stj it says "mexico" and appears to be a solid state device of some sort. initially I thought a diode package but looking at how the circuit seems to work it seems more likely to be a relay. For Budm pictures attached

White and black wires are tied into the amp meter, red go to timer just seem to be missing that unknown component to make it work again

[RCA2000]

Re: Kent TR36 Golf cart charger

Not really sure...but it looks like a TRIAC of some sort...to ME...

[budm]

Re: Kent TR36 Golf cart charger

I see bridge rectifier fed by the power transformer in this picture:
https://www.badcaps.net/forum/attach...6&d=1456983446
So that blown up device may be SCR or something like that for pulse charging.

[redwire]

Re: Kent TR36 Golf cart charger

I see the MOC3011(?) driver IC opto isolator, so it looks like a phase-controlled charger. But the transformer has an extra winding going to an oil-filled capacitor, so I'm going to guess it's a ferro-resonant transformer with the cooked part an isolated-tab TRIAC similar to ones used in microwave ovens and such. The bridge rectifier goes right to the battery, looks like. That's why I don't think it's an SCR, but I could be wrong. I can't see all the wires. Black wire is the gate.

If you can't make out the markings, I would look here: http://www.sanrex.com/semiconductors/discretes/triacs/

I would ohmmeter the MOC3011 and see if it got taken out when the TRIAC shorted. And check all the semi's (bridge rect.).

[Caleb]

Re: Kent TR36 Golf cart charger

That is looking very promising there are no other markings I can find, they could have been on the piece that was blown off. Any idea how many amps this thing would need? it has a 15 amp fuse would I be safe with a 25 amp version? Or should I go higher? bridge rectifier tests good, will ohm out the moc3011

edit, i just found the 35 amp version pretty cheap would that be suitable?
moc3011 is testing ok no continuity between triac and diode junction is ok

[redwire]

Re: Kent TR36 Golf cart charger

I always use higher current/voltage triacs because it's only a few bucks more.
If you know the charger's max. output watts, you can figure out how many (average) amps the part would see. The triac ends up getting poor heatsinking on the steel panel, so it would never achieve the datasheet rating.

Another popular chassis mount triac that I think would work: is St Microelectronics BTA40-600B (or higher voltage for $9)

You could probably use a 100W light bulb in place of the triac to see if the rest of the charger comes to life and is ok.

[Caleb]

Re: Kent TR36 Golf cart charger

Thanks I ordered a 35 amp, and will give it some heatsink paste when I put it back in. In theory it should be capable of 4200 watts/ 36v=116 amps, I dont think it outputs that many watts. At least if I know what the heck it is I can upgrade it later.

[budm]

Re: Kent TR36 Golf cart charger

The POWER dissipation on the device will be the Vdrops across the device * the current flowing through the device, the load will be the one that dissipate the large power, so the power dissipation on the device must not exceed the spec of that TRIAC, proper heatsink will be required to keep the device in the safe operating condition so it will not blow up.
These at MOUSER (http://www.mouser.com/Search/Refine.aspx?Keyword=bta40) have 1.8V.
Also the GATE Trigger current (igt) for the above is 100mA.

The SANREX: http://www.sanrex.com/semiconductors...kage/standard/
which looks like what is used in your unit only required 50mA of igt.
So you have to see what the resistor value is being used at the GATE.
See PDF for learning.
http://electronics.stackexchange.com...-gate-resistor

http://electronics.stackexchange.com...age-of-a-triac

https://cdn.badcaps-static.com/pdfs/...a63088770f.pdf

So hopefully the GATE drive circuit (OPTO, RESISTOR, etc) on that board will provide enough GATE current to turn on the TRIAC.

[mxslick]

Re: Kent TR36 Golf cart charger




Looks like the power transformer is cooked...you should try to check it before powering it up again. Measure resistance of each set of windings, and from ALL terminals to the transformer frame.

All the damage is either from the triac failure, or a short in the transformer, or even possibly an overvoltage on the incoming AC line (spike, surge or lightning strike..)

[Caleb]

Re: Kent TR36 Golf cart charger

Mxslick I think most of the black stuff on the transformer is carbon from the triac exploding.

Budm as you suspected I got the part in last night and the gate isnt triggering, I will have to figure out the proper gate resistor, I got the sanrex replacement with the smaller gate current. With everything tied together I am only getting 1.2v to the gate. Ran out of time last night was working on another plasma board too.