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Main => Monitor/Video Forum => Topic started by: OverRide on November 07, 2011, 08:30:40 pm

Title: Isolation transformers question.
Post by: OverRide on November 07, 2011, 08:30:40 pm
Hello,

I wanted to confirm that I could use this as a monitor isolation transformer:
(https://lh6.googleusercontent.com/-BI_9CsdFEHs/TriDRNcxsfI/AAAAAAAABu8/wZUV5LWyJJ8/s400/P1030342.JPG?gl=US)

I am use to seeing them look like this:
(https://lh6.googleusercontent.com/-yfqy6bQuqcw/TriFNYQU5pI/AAAAAAAABvM/My02rLccqxI/s800/isolation%252520transformer1.JPG?gl=US)

If I can use the type in the first picture how would I wire the monitor's power properly since it has only two wires for power and those transformers are set to accept 3-prong.

Thanks.
Title: Re: Isolation transformers question.
Post by: MonMotha on November 07, 2011, 08:44:19 pm
Are those step-up/down transformers in your first picture?  Those are usually NOT isolating transformers; they're autotransformers.  You can check by measuring (with it unplugged!) continuity between the output side and input side.  If there's any continuity (low ohms measurement) between both hots or both neutrals (ground is fine and expected), then it's autotransformer, not an isolating transformer.  It will be normal to measure nearly a short between hot and neutral on one side regardless of transformer type, so don't be alarmed.
Title: Re: Isolation transformers question.
Post by: fredster on November 07, 2011, 08:50:08 pm
I've seen those old type of transformers in some machines.  You have to be careful with old Sega stuff, as some of them stepped down/up the power. You can check the output and see if it steps up the power with a multimeter.  Plus what MonMotha mentioned)

Any idea where they came from?
Title: Re: Isolation transformers question.
Post by: OverRide on November 08, 2011, 08:25:18 am
Thanks guys. I will test them out, but I am pretty sure they wont be isolation transformers. As far as I know it was a regulatory compliance thing to have these transformers installed in a cab while in the wild.  I picked them up for free and was hoping they served the same purpose but am guessing not given your responses.
Thanks!
Title: Re: Isolation transformers question.
Post by: MonMotha on November 09, 2011, 07:57:32 am
Are you in Canada?  Apparently certain places in Canada (I believe Ontario at least, but perhaps others) require the entire cabinet be run off an isolation transformer.  The story I heard was that some poor kid electrocuted himself due to an improperly wired/grounded/faulted (i.e. triple failure) cabinet in a wet location once, so the legislature somewhat naively required them on all arcade games going forward.  If that's where those came from, they probably are indeed isolation transformers.

Easiest is to just check as above.  If the primary (input) shows any continuity to the secondary (output), then you've got an autotransformer.  If it reads open (infinite or very high ohms), then you've got an isolation transformer.  If the output and input voltages are the same, then you've probably got an isolation transformer (since a 1:1 autotransformer is pretty pointless).
Title: Re: Isolation transformers question.
Post by: OverRide on November 09, 2011, 12:27:41 pm
Yes I am in Ontario and there was/is a requirement to have a transformer installed in every arcade cabinet. Most guys take them out for home use (hence how I acquired these for free). A cabinet I gutted years ago came with one and it was in front of all power coming into the cab there was also the manufactures isolation transformer for the monitor.

I put the multimeter on the transformer set to ohms and nothing happens to the reading just maintains "1.". When I put it on the ground it jumps around until it hits 0. The specs labeled on the one transformer has the same input and output.

Looks to be isolation transformers.

The monitor I want to use along side this iso transformer has only hot and neutral. How would I correctly wire it to the trasnformer? Simply send the ground to the frame?

Thanks for your help guys!
Title: Re: Isolation transformers question.
Post by: OverRide on November 09, 2011, 02:19:42 pm
Cap kit
:dunno
I might need one. Cant tell until I get power to the monitor :)
Title: Re: Isolation transformers question.
Post by: kardenm on November 09, 2011, 03:10:01 pm
Cap kit

WHAT does that have to do with this post?? :dunno
Title: Re: Isolation transformers question.
Post by: Q*Bert_OP on November 09, 2011, 03:39:04 pm
 :lol