Hammond 272jx power hookup question
« on: December 30, 2018, 12:12:40 PM »
Hi all, I've got a Hammond 272JX power transformer and the primary has hookup for 125V or 115V. My wall voltage is 120V, which tap should I use?


Re: Hammond 272jx power hookup question
« Reply #1 on: December 30, 2018, 12:27:07 PM »
If you used the 125v, I'd guess the secondary output would be less than rated and,  this could be an issue for things like heaters..??? I'd rather have too much than too little..... so I'd say the 115v....maybe test for yourself....??

I'd be interested to hear more on this..... is there a tolerance anyway that makes this moot???

Re: Hammond 272jx power hookup question
« Reply #2 on: December 30, 2018, 12:36:25 PM »
In that case either will work , you will of course have a slight difference on volts depending on which tap you use , I believe the usual advice is pick a tap just above what what your line voltage is . I have used mains transformers with 220 volts taps at the nominal 234 volts here , just gives a small amount of extra voltage on the 6.3 ac volts line which just allows you to regulate it down to 6 volts or so dc , and some extra ht volts . Transformers are well capable of a few extra volts on the primary without any trouble , Id say check your requirements and choose the most suitable tap for your useage,  ' 6 of one half a dozen of the other ' is the saying that springs to mind . One way your< 5% up on volts the other <5% down from nominal . Depending on the current you draw one tap will suit better than the other ,for instance if your Lt current is low compared to what the transformer can provide ,you'll probably get closer to 6.3volts on the lower voltage tap. 


Re: Hammond 272jx power hookup question
« Reply #3 on: December 30, 2018, 01:21:36 PM »
Thanks all, didn't know if there was a general rule of thumb for this so I'll try the higher tap first and see what happens.


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