Minimum Volt Amp Transformer for 1 bay with 10 push button

[Keno]

Hi group, had a 24vac 100va transformer give up to the ghost, have 1 on order. I have a 40va transformer in stock, can I use that to get my bay up and going while I wait on the 100va replacement to get delivered? Don't want to screw something else up by using a lower powered transformer, so thought I'd check with the forum.

This transformer powers 1 SS bay with 10 push button Ginsan meter box.

 

[MEP001]

The 40va will probably work, but it probably has a small fusible link inside that might blow. I don't believe you will harm anything but the transformer by trying it.

FWIW I have several times run a pair of wires off the next bay's transformer to another one while I waited on a new unit.

 

[Keno]

The 40va will probably work, but it probably has a small fusible link inside that might blow. I don't believe you will harm anything but the transformer by trying it.

FWIW I have several times run a pair of wires off the next bay's transformer to another one while I waited on a new unit.

Thanks for the idea, may try your way with a fuse inline just in case a short or something else took out the original transformer. The fuse on the transformer wasn't blown, but the transformer is not putting out the secondary 24vac and has a burnt smell. I think it got sprayed with tire cleaner from a busted hose last night and took out the transformer out and burnt it out.

 

[MEP001]

I would bet it just failed, could have been from the tire cleaner. An inline fuse isn't a bad idea, 1 amp fuse if you can find some. I just worked on a wash where the soap solenoid fell out of the coil which burned up, the fuse on the transformer was 5 amp, idiot attendant turned the bay back on while I was gone and melted the timer.

 

[Keno]

What amp rating fuse should I be using in the transformer on the permanent install? I am pretty sure the fuse that is in there currently is way too big.

 

[MEP001]

It's enough to protect the transformer. I've recently worked on two washes that both had a solenoid coil fail and cause a dead short. The 5A fuse protected the transformer and timer. One of the washes has a small 2A breaker for the low voltage which tripped before the fuse blew. The breakers are about the same price as a replacement fuse. I think 5A might be the smallest fuse that fits in the transformer holder.

 

[Keno]

Update, found a used transformer and installed. I put an inline fuse holder on the 24vac hot. 1 Amp fuse blew instantly. 2 Amp fuse powered everything while adding coins, blew as soon as I chose first function. I have a 5 Amp in there for now to get the bay going for the weekend. Thinking I need a 3amp in there for permanent install.

 

[Dan kamsickas]

Update, found a used transformer and installed. I put an inline fuse holder on the 24vac hot. 1 Amp fuse blew instantly. 2 Amp fuse powered everything while adding coins, blew as soon as I chose first function. I have a 5 Amp in there for now to get the bay going for the weekend. Thinking I need a 3amp in there for permanent install.

What is the VA rating of the transformer. If it's 100va you don't want a fuse larger than 4 amps (100/24=4.17amps)

 

[Keno]

Yes, it is 100va. 4 amp fuse would have to be ordered online. Home Depot only has 3 or 5 amp available in store. Will try 3 amp first, if that doesn't work will step it up to 4 amp.

 

[MEP001]

I just bought a couple of the 5 amp at Home Depot. Mouser showed a 6 week lead time on theirs, and they're three times the price. 5 amp will protect the transformer.

 

[mjwalsh]

I just bought a couple of the 5 amp at Home Depot. Mouser showed a 6 week lead time on theirs, and they're three times the price. 5 amp will protect the transformer.

Keno, Just so you are aware that because of more precise protection ... the 4 amp is the better choice IMHO.

 

[Keno]

Bought some 3 Amp fuses at Home Depot, if those blow will order 4 Amp online

 

[Randy]

There’s a reason that a fuse blows and that’s because the circuit is overloaded. A few months ago I sold a couple of Dixmor LED-7 timers to a customer. A week or so later he brought one back melted. When I asked him what happened he said that the fuse kept blowing so he kept going up to the next size fuse until it didn’t blow and the timer melted. He thought that it should be covered under warranty.

 

[Keno]

Ok group, did an amp draw measurement today while the bay was running with a function selected. It is hovering right at 2.99-3.04 amps, so obviously a 3 amp fuse will not work, I will order the 4 amp online from Home Depot and install that.

Question for the group - is that within the "normal" amp draw range on the 24vac circuit for a bay? These are older Ginsan 10 selection push button boxes with GS402 timer and an older inbay Ginsan display.

 

[MEP001]

I've never done a load test.

 

[Dan kamsickas]

I just bought a couple of the 5 amp at Home Depot. Mouser showed a 6 week lead time on theirs, and they're three times the price. 5 amp will protect the transformer.

Ohm's law says not to exceed 4 amp for the fuse.

Question for the group - is that within the "normal" amp draw range on the 24vac circuit for a bay? These are older Ginsan 10 selection push button boxes with GS402 timer and an older inbay Ginsan display.

That setup really shouldn't pull much over an amp in and of itself and usually less. The majority of the draw will come from what that board is turning on(solenoids, contactors, logic controls, idiot lights, etc). If you have a bill acceptor those can draw upwards of an amp when cycling and a MicrocoinQL pulls between .5 and 1 amp.

 

[Keno]

Ohm's law says not to exceed 4 amp for the fuse.

I have some 4 amp fuses on the way, will get it replaced when it comes in. I can't say I am too worried about it though, circuit was basically unfused for the last who knows how many years.

That setup really shouldn't pull much over an amp in and of itself and usually less. The majority of the draw will come from what that board is turning on(solenoids, contactors, logic controls, idiot lights, etc). If you have a bill acceptor those can draw upwards of an amp when cycling and a MicrocoinQL pulls between .5 and 1 amp.

My 3 amp reading was with HP Soap running, no bill acceptor, and Sensortron (will be replaced with MicrocoinQL to switch site to tokens)

 

[mjwalsh]

Ok group, did an amp draw measurement today while the bay was running with a function selected. It is hovering right at 2.99-3.04 amps, so obviously a 3 amp fuse will not work, I will order the 4 amp online from Home Depot and install that.

Keno ... a thorough amp draw test ... with hopefully the maximum plausible # of devices turned on the circuit is a good idea IMHO. Especially if you have a employee with a clipboard to help assist to make the data collection process more straight forward.

A non invasive clamp on meter is by usually the best & most efficient way to do the test. My Fluke 325 is great for that & I have another fluke (771) that will actually measure tiny milliamps that I use way less often. The PLC dog wash we have has some environmental devices so the 771 is more for milliamp transducers etc.

 

[Keno]

I used a clamp meter, I am ok with the 4 amp fuse without further testing, as it is a little lower than the 4.17 amps the transformer will put out, basically just want to protect the transformer.

 

[Keno]

4 amp fuse has been installed for about 1.5 weeks without blowing