Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives :: Books
Support This Site: Contributors :: Advertise


It is currently Jun Thu 21, 2018 9:18 am


All times are UTC [ DST ]





Post New Topic Post Reply  [ 7 posts ] 
Author Message
 Post subject: Another Variac Question / Application?
PostPosted: Mar Mon 05, 2018 12:29 am 
Member
User avatar

Joined: Apr Sun 23, 2017 11:22 pm
Posts: 182
Location: 44035 (Near Cleveland Ohio)
I found an odd variac in my 40-year-old junk collection that has me wondering. It's a General Radio Type 60 Variac. Mfg date 3/1956. On the terminal connection board it says "Do Not Use Below 400 (cycle symbol)" . The only other numbers on it are 5950, and 7614974. Any ideas as to usage? It has the usual 5-terminal pinouts. I was searching for a variac/large rheostat to build a model railroad power supply and I stumbled on this - - totally forgot I had it.

Any info would be appreciated.

Dan


Top
 Profile  
 
 Post subject: Re: Another Variac Question / Application?
PostPosted: Mar Mon 05, 2018 1:17 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 17432
Location: Albuquerque, NM 87123
It was used in aircraft.


Top
 Profile  
 
 Post subject: Re: Another Variac Question / Application?
PostPosted: Mar Mon 05, 2018 2:03 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 32700
Location: Maryland 20709, USA
It means what it says. Don't use it below 400Hz.

It's designed for use with aircraft electrical systems.

Transformers designed to operate at 400Hz require much less iron than those for 60Hz.
That's why they use 400Hz for aircraft AC power.

- Leigh

_________________
73 de W3NLB
http://www.AtwaterKent.info
Click "Grebe Stuff" for Synchrophase info


Top
 Profile  
 
 Post subject: Re: Another Variac Question / Application?
PostPosted: Mar Mon 05, 2018 4:23 am 
Member
User avatar

Joined: May Wed 18, 2011 2:40 am
Posts: 3369
Location: Littleton, MA
Assuming it is rated for 120 volts at 400 Hz, I believe you could use it at 60 Hz if you limit the input voltage to 12 volts. This might be sufficient for your model railroad needs. Just put the step-down transformer before the variac rather than after it.

You’ll need to check through old General Radio catalogs to find the voltage rating for your variac, assuming it was a standard item rather than a custom order. Scans of the catalogs are available on the IET website.

_________________
Steve Byan http://www.byan-roper.org/steve/steve-at-play/


Top
 Profile  
 
 Post subject: Re: Another Variac Question / Application?
PostPosted: Mar Mon 05, 2018 3:10 pm 
Member
User avatar

Joined: Dec Tue 23, 2014 6:51 pm
Posts: 718
Location: N. Palm Bch, Fl.
In the service, I worked on Mobile Ground Radar and our Height Finder ran off a 400 cycle generator while the Search Radar was 60 cycle. Never knew or asked why. It was a turbine generator that used Av Gas. What you have there must be old military or Commercial Aviation as said above.

Crazy what you remember years ago, but can't remember where you put my glasses.
Freeman.


Top
 Profile  
 
 Post subject: Re: Another Variac Question / Application?
PostPosted: Mar Mon 05, 2018 4:12 pm 
Member
User avatar

Joined: Feb Sun 02, 2014 9:13 pm
Posts: 1775
Location: Roanoke, VA
The Type 60 was an old model designation for some GR 400 Hz Variacs prior to 1958. The 60-AU was uncased and the 60-AM was cased. Yours may be a somewhat different Type 60 if it was made under military contract.

_________________
Dale H. Cook, Antique Radios / Test Equipment (GR/HP/Tek)
http://plymouthcolony.net/starcity/radios/


Top
 Profile  
 
 Post subject: Re: Another Variac Question / Application?
PostPosted: Mar Tue 06, 2018 3:34 am 
Member
User avatar

Joined: Apr Sun 23, 2017 11:22 pm
Posts: 182
Location: 44035 (Near Cleveland Ohio)
Thanks for all of your help. After looking up the specs on the General Radio archives (great tip - - thank you!), I decided to sell it. It's in great shape, and maybe someone might be able to use it at it's design frequency (400 - 2600 hz). After thinking about it, I vaguely remember using it for a variable frequency motor control project back in my college days (around 1970). I only wish I could remember more of what I learned back then - - -. Thanks to all of you, bits and pieces are being coaxed back into the present. "Use it or lose it" is making more and more sense to me these days . . . . in more ways than one :wink:

Dan


Top
 Profile  
 
Post New Topic Post Reply  [ 7 posts ] 

All times are UTC [ DST ]


Who is online

Users browsing this forum: Google Adsense [Bot] and 10 guests



Search for:
Jump to:  
























Privacy Policy :: Powered by phpBB