Does higher than spec voltage affect appliance operation?

Hi,

I have a vending machine which was working a day prior to it not. The location of the machine has changed. So it worked for 10 min, after which I shut it down. When switching it on the following day, there was no power to lcd etc. I swopped the pcb and transformer(ac to dc) with one at another location which was working, to no avail. I check in the machine manual to notice that the spec specified 220 - 230VAC. I measured 216 at the sight with no problem, and 247V at the problematic site. Can this voltage diff cause the machine not to work?

Regards,
Dion

With anything remotely modern it wouldn't be any problem - with some very old gear it may be.

However, you don't have your location filled in - so I have no idea what your mains is supposed to be.

diono said:

Hi,

I have a vending machine which was working a day prior to it not. The location of the machine has changed. So it worked for 10 min, after which I shut it down. When switching it on the following day, there was no power to lcd etc. I swopped the pcb and transformer(ac to dc) with one at another location which was working, to no avail. I check in the machine manual to notice that the spec specified 220 - 230VAC. I measured 216 at the sight with no problem, and 247V at the problematic site. Can this voltage diff cause the machine not to work?

Regards,
Dion

Click to expand...

Welcome to ETO, diono.

Since you swapped in a known, good PCB and transformer and it apparently did nothing, I'm thinking that perhaps there may be a blown fuse, especially with the voltage variations you seem to be experiencing.

That sort of poor mains voltage regulation might also imply the chance for even more serious line surges.

Often fuses on older equipment was located at a place in the equipment other than the PCB(s).

Thanks. I live in South Africa.

Why don;t you drop the voltage? Take a suitable (current wise) 24 VAC transformer. Set primary normally. Place the secondary in series with the 247 V. IMPORTANT- DO NOT connect the appliance, until verifying that the output is 247-24V and not 247+24V. If it's the latter, reverse either the primary or secondary and TEST AGAIN.

Now connect your machine to the now 247-24 V power supply.

I just had a look at the spec for the machine:- 230V, 50Hz single phase via a 13Amp switched socket or fused spur. Please forgive my ignorance, but what are is a 13Amp switched socket and fused spur? Also, are there any common devices at home from which I can use the 24VAC transformer? Many thanks.

diono said:

I just had a look at the spec for the machine:- 230V, 50Hz single phase via a 13Amp switched socket or fused spur. Please forgive my ignorance, but what are is a 13Amp switched socket and fused spur? Also, are there any common devices at home from which I can use the 24VAC transformer? Many thanks.

Click to expand...

Switched socket:
**broken link removed**

Fused Spur:
**broken link removed**
This device is where I'd look for a problem.

Often (at least in the US) a door chime (bell) or an AC controller device is fed from a 24VAC transformer.

A doorbell is usually 16 VAC. 24 VAC, 40 VA transformers are found in furnaces. 24 VAC is a common control voltage.

KeepItSimpleStupid said:

A doorbell is usually 16 VAC. 24 VAC, 40 VA transformers are found in furnaces. 24 VAC is a common control voltage.

Click to expand...

Oops. Thanks KISS on the doorbell voltage. Mine is, actually, 24VAC but apparently it is not the norm.

Yea, dad put one in 52 years ago from the old house even. Still works. A real plunger thingy. It doesn't even look pretty. He did wire a switch so it could be turned off for Halloween. An interesting touch.

A wireless extender was added and it croaked long ago. Used about four D batteries in the bell.

PLANS (famous last words) include replacing the old wireless doorbell for the back door with a Linear DXS transmitter. I already put one inside of the old wireless housing. The DXS transmitters are used in alarm systems, so they are very reliable. The transmitter was essentially free anyway. I took apart a sealed pendant xmitter because the battery went dead. To maintain the waterproof status, the battery is not replaceable. They changed the design to use two CR2032 batteries in parallel so the xmitters last longer.

I really want to get back to work on that project and other related ones.