Replace old 110v 60 cycles transformer?
September 12, 2015 6:33 AM   Subscribe

I have this transformer in my basement. It buzzes quite loudly. Is it possible for me to replace it with something from a hardware store? If so, what would I replace it with?
posted by merocet to Home & Garden (7 answers total)
Depends on what it is for. Do you have a voltmeter to determine what its output voltage is (on the bare terminals)? If it is for the doorbell (you could unhook one of the wires and then see if the doorbell still works, assuming that the output is 12 volts or less so that you don't hurt yourself doing so) you can then take a look at the doorbell to see what voltage it needs, and then get a new replacement that meets those specifications from the hardware store.

Otherwise, you need to figure out what it is supplying power to before you change it.
posted by BillMcMurdo at 6:48 AM on September 12, 2015

Absolutely seconding Bill above, but if you can take it off the wall (after turning off power to it of course) and find some bolts or screws holding the laminations together and then tightening them, you may be able to reduce the buzz.
posted by deadwax at 6:51 AM on September 12, 2015

Looks like this is for powering a doorbell. Unhook one of the wires on the bottom (maybe the one on the right) and try ringing your doorbell(s). If they don't work, and did before you unhooked the wire, you have your answer.

I'm not sure what's up with the lower left-hand (white?) wire. That one is an oddball here.

Can you take the cover off and take another picture? The two wires coming in from the top make it seem like there is a junction, and you'll need to install a box for that too.
posted by achrise at 6:51 AM on September 12, 2015

Best answer: Ace lists a transformer with the option of output: 8, 16, or 24.

Heath Zenith Tri Volt Transformer (SL-125-01)
sku 36485 | 082901364856
Product Details
2-1/2"L x 2-1/4"D x 2-1/8"H
Output: 8 VAC-10 VA, 16 VAC- 10 VA, 24 VAC-20 VA
Input: 120 VAC

Most transformers of this type are low voltage output AC - note the knurled nuts on the bottom connectors. Those are designed to be tightened by hand. Due to the lower voltage, they are generally safe to handle when engergized. They are commonly used for doorbells or buzzers or furnace control thermostats, etc. Most bells and buzzers will operate on 16 VAC. Most furnaces on 24VAC.

The cloth covering on all the wires reveals that it has been in place for perhaps 60+ years.

Be very careful with the upper (120VAC) input wires. Turn off the power at your fuse/circuit breaker box. Cloth covered wires of this age crack and crumble with handling. If possible trace them back to the nearest junction box and replace them with new wires.
posted by tronec at 7:28 AM on September 12, 2015

Not to be an alarmist, but cloth wire insulation often contained or was coated in asbestos. Which is could be dangerous if the fibers get loose and float about in the air. So be very careful about removing that transformer. Dust mask and gloves at the very least for protection.

To be clear asbestos in household wiring is/was rare. It was usually reserved for high heat situations, so there my be no issue with your transformer.
posted by Zedcaster at 10:00 AM on September 12, 2015

Probably a doorbell transformer. I had the same issue at my house. Got a new one at Home Depot for around $20, wired it in, and we're good. I sincerely doubt there's asbestos in your wiring. When you take the old one out, just toss it in the trash, or leave it on top of your trash can so a scrapper can pick it up and get a dime or so for it.
posted by Slinga at 10:07 AM on September 12, 2015 [1 favorite]

Response by poster: I gave this a tap with the blunt end of a screwdriver and it quietened right down. I'll replace it soon but it's less urgent now. Thanks for all the answers.
posted by merocet at 12:12 PM on September 19, 2015

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