Spectrum Transformer Excessive Heat

HHRR · February 16, 2009, 02:22:09 PM

My spectrun transformer becomes extremely hot on the top surface around the dial, after only 10 minutes of operating my 2-6-0 and 4 cars at about half load. Then, the power decreases, then increases again, after a short time as if a thermal overload switch kicks in and out. I took off the dial, and the metal post was so hot you could not touch it but for a few seconds. My layout has not really changed (simple loop and a side track). The transformer is 10 years old and came with the train set. I know transformers become hot, simply from its operation, but this is excessive and started this year. Time for a new one? Any ideas would be appreciated.

Joe

Joe Satnik · February 16, 2009, 03:27:21 PM

Can the case be taken apart easily?

Joe Satnik

HHRR · February 16, 2009, 03:59:04 PM

Yes, taking it apart is not difficult. I did not try it yet.

Joe

Hunt · February 16, 2009, 04:15:23 PM

Joe a concern... without proper training someone can unknowingly create a hazardous or even deadly condition poking around in a transformer or power pack.

I don't believe we should provide any procedure that requires opening the case.

Joe Satnik · February 16, 2009, 04:44:56 PM

Hunt,

Thank you for the warning.

I forgot to tell him to unplug it from the wall if he was going to take it apart. (No danger unplugged.)

Joe HHRR,

Contact me off board for further advice.

joebarbATwwtDOTnet

Sincerely,

Joe Satnik

Joe Satnik · February 17, 2009, 11:34:47 AM

Dear Joe HHRR,

Are you using the accessories terminals? Do you get the same symptoms with the accessories disconnected?

Sincerely,

Joe Satnik

HHRR · February 17, 2009, 12:21:12 PM

Dear Joe Satnik,

I'm using the DC accesories terminals to light two grain of wheat bulbs in my depot. I doubt that this would cause the problem, but I will try it tonight without it. I am not using the AC accessories terminals.

Thanks, Joe

Joe Satnik · February 17, 2009, 01:48:07 PM

Interesting,

This is the first time I've heard of a DC accessory output. Is it variable with the speed dial or a steady voltage?

Joe Satnik

HHRR · February 17, 2009, 02:04:04 PM

Sorry Joe I may have confused the issue. I connected my light bulbs to the DC power (screws) that feed power to the track. Therefore, my lights vary with the speed.

Joe

Joe Satnik · February 17, 2009, 06:34:37 PM

Disconnect everything and see if it overheats at zero throttle, half throttle and full throttle.

BIG BEAR · February 18, 2009, 01:08:41 AM

Hey Joe,
From my experience and following bachmann's, to tyco's directions the ONLY thing to be attached to the DC terminals is the track to run the train, all other accessaries are to be run from the AC terminals.

Enjoy,
Barry

Joe Satnik · February 18, 2009, 10:50:50 AM

To clarify:

Disconnect all loads from the outputs of the power pack.

Plug into wall.

See if it overheats at zero throttle, half throttle and full throttle settings.

Thanks.

I've repaired power packs. Unless there is extensive damage (unlikely), they are usually fixable.

Sincerely,

Joe Satnik

railtwister · February 18, 2009, 12:16:13 PM

Quote from: jestor on February 18, 2009, 09:49:52 AM
I believe the total output of the Spectrum Pack is 10VA. That isn't much; probably just enough to run the train, especially if there are any lighted cars in the train. Usually building lights are 18 volt AC bulbs which should never be run off the DC terminals. You have probably been exceeding the power limit of your pack all these years and it is finally now protesting the abuse. DO NOT TRY TO TAKE IT APART, unless you are a qualified service tech. I'd suggest upgrading to a more powerful pack and let this one retire from service.

Actually, most incandescent bulbs used in model railroading will work on AC or DC, and they don't really care which. LED's REQUIRE DC, and true flourescents need AC because their starters are transformers. Running an 18volt bulb on 12 volts will work OK too, it just means that the bulb will not burn as brightly, and will run cooler & last longer than it would on 18 volts. If the output of the power pack is marginally adequate for the train, then it is true that adding two extra light bulbs could push it over the edge, causing it to overheat and go into overload. If the rated output of the powerpack is only 10VA, then it probably is marginal for just the train by itself, and the extra bulbs could be just enough to cause the problem described. Changing to a better quality power pack with higher output is probably a good idea in any case.

Regards,
Bill

HHRR · February 18, 2009, 04:04:09 PM

Guys,

I appreciate all the input. To clarify, the 2 bulbs I am using for the depot are the same type of bulbs as in the passenger cars (grain of wheat). So, I connected the depot lights to the DC terminals, and they run off DC like the car lights. The wires to the bulbs are about 12 inches long. (maybe this is a resistance problem, since the wires are so fine). I like the yellow glow from the lights in the depot, as it reminds me of old kerosene lanterns. I do not use higher voltage AC bulbs. Can the grain of wheat bulbs run off AC also? In addition to the lights in the depot, I run 3 lighted passenger cars (2 bulbs per car) with my 2-6-0. Tonight I'll try the transformer without any load, then with the train only, and see what happens. Thanks.

renniks · February 18, 2009, 06:33:24 PM

Joe(HHRR)

Suggest you get a cheap wallwart to power your depot lights and have steady level of lighting. To have the lights vary with the speed of the train and go out when the train stops at the depot seems rather strange arrangement.
I have a wallwart which is switchable between 3 and 12 volts DC--get one of these and try the 6 or 9 volt setting for your kerosene lamp effect.

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Spectrum Transformer Excessive Heat