Carwash Transformers...

[Twodose]

What is a good VA size for an individual transformer for each bay in a self-serve?

And can a bad transformer vary in its output, or are the either working or not working?

 

[MEP001]

100 VA should be plenty for most bays even with a bill acceptor - I went with 150 when I installed the credit card system that draws off the same transformer.

I have a bay acting up that I think the transformer is failing. I've replaced every other component and the transformer is the only other thing I suspect. As a rule though, they either work or fail and release smoke.

 

[cmacar]

you can not go wrong with a 150 va transformer, 75va is the lowest you can go on a small system, power draw combined with modifications for more functions can cause wierd problems, don't forget to have proper grounding to prevent a floating ground, this condition will cause extreme troble shooting problems. also use a 4 amp slo blow fuse on the 24 volt side

 

[mac]

You know it's easy to become jaded and not appreciate the level of expertise that is offered for free here. When my wife, who works part time in my office, hears me giving out free advice on the phone, I hear about it.

 

[MEP001]

don't forget to have proper grounding to prevent a floating ground, this condition will cause extreme troble shooting problems.

If the transformer is fed with two legs of power and not with 120V/common, you shouldn't ground one 24V side. 240-24V transformers give two 12V AC legs of live power.

 

[Twodose]

Currently I am using the Micron group C 120x240 volt transformers, they are 75Va, I am using them 240v, they seem like a good quality transformer, they were the same transformers that were in the wash when I purchased it in 1986, at that time there was only soap, rinse, wax, we added TC, and FB and also GS-31’s in the bays, I have been considering installing the cryptopay CC system, do you think the 75va will be enough for the addition or should I go to a 100va or possibly 150va? I don’t ever plan on using an in bay bill acceptor because of the area I am in, there is a wash down the road that installed new boxes from KR with the in bay bill acceptors and within a month they were broken into.

 

[MEP001]

100VA should be plenty. I have in an emergency run two bays off one 100VA transformer, and that's with bill acceptors, AND they were the wrong voltage (240V transformers on 208 incoming voltage).

 

[mjwalsh]

you can not go wrong with a 150 va transformer, 75va is the lowest you can go on a small system, power draw combined with modifications for more functions can cause wierd problems, don't forget to have proper grounding to prevent a floating ground, this condition will cause extreme troble shooting problems. also use a 4 amp slo blow fuse on the 24 volt side

cmacar,

I agree with your statement about preventing a floating ground. I am glad that is one of the things that our original installer Specialty did correctly. I just want to share is that when we added temperature controlled heaters to help keep the boxes drier we bought a reasonably priced 200VA transformer off of Ebay. We use that separately for all 6 of our bays independent of the bay controls. That way the box stays heated even though we may have the bay controls shut off on one of our tandem bays. We calculated the total wattage for all six on at once & we discovered that a 200VA was needed for a reasonable margin. It has been about 5 months now & so far it has made sense to use this approach with the heat elements. Otherwise, we have 100VA - 4 amp fuse for each bays just in case we add something in the future. No one has a crystal ball when it comes to a future in bay solenoid or whatever.

mike http://kingkoin.com/USA_Deficit_Reduction.html

 

[Twodose]

What is the proper way to prevent a floating ground?

This is from Micron:

75va<transformer ÷ 24v = 3.12 amp. x this by 1.67 (167%) <allowable % of overcurrent = 5.21 amp.

I was having problems when I purchased all new ginsan gs-401 timers for the bays, I had installed momentary switches (stop and start) on each bay inside the equipment room to use when cleaning the bays, it would short terminals 2-3 to stop the timer which worked fine on the older ones, but not on the new ones, I didn’t change anything except the timers, ginsan came to the conclusion that shorting the newer timers in the same way would cause a surge and blow the fuse. Go figure, now I can only stop the timer on the timer itself by hitting the mode button and clear.

 

[MEP001]

What is the proper way to prevent a floating ground?

Use a 120V transformer and then you can ground the common side of the 24V wiring.

It's not a problem to have a floating ground with a 240V to 24V transformer.

 

[2Biz]

I have 75va Transformers for each bay. Keep in mind that only 3 solenoids or fewer and the display will be putting a load on the transformer at any given time. Only one function at a time. The biggest load on the transformer will be the coin box heater and will have to be factored in. Even with 15-20w heaters and 3 solenoids energized, you're looking at about 1.5 amps load on a 75va transformer capible of 3.12 amps...There is 50% capacity left.