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THE AM BULLETIN BOARD => QSO => Topic started by: N3DRB The Derb on January 16, 2009, 09:40:51 PM



Title: got this Megohmeter on ebay for 10 bucks + shipping
Post by: N3DRB The Derb on January 16, 2009, 09:40:51 PM
figure I can use it for hi pot testing. What are some other good uses for this thing? Don't you use this for ground system testing as well? Its a Freed 1020A.


Title: Re: got this Megohmeter on ebay for 10 bucks + shipping
Post by: W1UJR on January 17, 2009, 05:09:19 PM
Cool find Derb!

Think Gary W1ZM, the xformer guy, has something like it on his bench.


Title: Re: got this Megohmeter on ebay for 10 bucks + shipping
Post by: Jim, W5JO on January 17, 2009, 05:17:19 PM
Good find and very useful for testing HV circuits, transformers, chokes and the like.  Will come in handy when you finish rebuilding the amplifiers.  Use it to check the HV wire you use.


Title: Re: got this Megohmeter on ebay for 10 bucks + shipping
Post by: N3DRB The Derb on January 17, 2009, 05:26:30 PM
also figgered it might be good for checking hamfest transformers.


Title: Re: got this Megohmeter on ebay for 10 bucks + shipping
Post by: WZ1M on January 18, 2009, 07:42:37 AM
Thats a good machine but lacks a liitle in the voltage department. The tester I have goes to 5KV and also checks leakage. I find that most of the tests I do on transformers results in insulation breakdown starting around 2.5 kv.
Regards,
Gary


Title: Re: got this Megohmeter on ebay for 10 bucks + shipping
Post by: W3NP on January 18, 2009, 09:15:47 AM
What Gary said. --- I use an Associated Research 4050DT that goes up to  5KV DC and 4KV AC. I too have found that bad things don't start to happen until between 2 and 3 KV.

I have seen the higher voltage units go for cheap prices at times.



Title: Re: got this Megohmeter on ebay for 10 bucks + shipping
Post by: KB3DKS on January 18, 2009, 09:25:21 PM
Gary, Dave,?

 About what is the allowable leakage current for these meg ohmers or for testing transformers in general?

 I have an HP precision CV supply that goes to 3kv at 6 ma max and also a much larger supply that will go to 2.5kv CC or CV but not both. The lowest current limit range is 0-5 ma., the highest 0-150ma. I have used these both for cap reforming and leakage testing.
 
   In other words.., how would you use a CV/CC type HV supply to test a transformer for breakdown without damage from the test?

  I have several old plate transformers that I would like to at least confirm if they
are usable or copper scrap.

 Bill, KB3DKS in 1 LAnd
AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands