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Old 23rd March 2012, 09:00 PM   #1
kendt is offline kendt  Canada
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Default help with power tranny

I have a power tranny thats been kicking around for a while. I misplaced the schematic for it. Is there a safe way to identify the voltages of the various wires coming out of it.
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Old 23rd March 2012, 09:20 PM   #2
DF96 is offline DF96  England
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Your first job is to make or borrow a lamp limiter.
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Old 23rd March 2012, 09:54 PM   #3
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.....or a variac
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Old 23rd March 2012, 10:41 PM   #4
kendt is offline kendt  Canada
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ok looks simple enough, Where do i go from there?
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Old 23rd March 2012, 11:02 PM   #5
DF96 is offline DF96  England
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Start by measuring resistances to find out which wire connects where. If possible, measure inductances too. The initial aim is to identify the primary, and see if it is tapped or has a 115V/230V pair.
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Old 23rd March 2012, 11:04 PM   #6
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Check the resistance across various pairs of wires to determine what's connected to what. If three wires show resistance between them, it's center tapped; determine where the ends are and where the center tap is (the center tap has roughly equal resistance to each end, and the ends have roughly double the resistance to each other compared to the center tap.

I usually connect the meter negative to one wire and test all the remaining wires with the positive lead. Then move the negative to a new wire and repeat until you've exhausted all of your combinations. Write down the various values, determine if any are center tapped.

Can you list the wire colors? If it's following any convention, that may get you far along quickly.

Once you've got your various R's you can then think about applying voltage. Do you have access to a variac or other means to limit the primary voltage/current?
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Old 24th March 2012, 04:49 PM   #7
kendt is offline kendt  Canada
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I tried to post a pic but had no luck. Here are the wire colors.
There are two white wire,s two brown wire,s and two green wire,s. All of these are very heavy guage (8ga)

The rest are smaller.
2x blue
2x yellow
2x orange
2x grey
1pr grn/red
1pr red/red,yellow
1 pr yel/blk
1 single purple.
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Old 24th March 2012, 05:50 PM   #8
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Can you post the various resistances between the wires?

Do you have access to a variac or other means to limit voltage/current?
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Old 24th March 2012, 07:37 PM   #9
kendt is offline kendt  Canada
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I will have to rig something up to limit the current. I will check the res. shortly.
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Old 24th March 2012, 07:54 PM   #10
kendt is offline kendt  Canada
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Ok here is what I get
rd/rd,yel 21ohm
rd or rd,yel across ppl 42ohm
yl/yl 8.0 ohm
rd/grn 2.5 ohm
all others 1.5 ohm
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