Just picked up a Heathkit Isolated Variable Power Supply and need some info

[vortalexfan]

Hello everyone yesterday I picked up a Heathkit Isolation Transformer with a Built-in Variac for $10 locally and it does work, but I would like to know some information about it like the variac specs and the wattage capabilities and how this compares to other Variable Isolated Power Supplies from the same time period as far as being able to handle various types of radios and or TVs.

Any help in this matter would be appreciated.

[ppppenguin]

I don't know about this specific model but there's a rule for all variacs. The maximum rating is the specified current. That's true at all voltages. I'll give an example for 120V countries. You have a 240 watt variac, so the plate will say 240W, 2A. If you set it to give 60V output, the maximum current is still 2A. Not 4A. If you take too much current you will burn the carbon brush and possibly damage the windings.

If it allows you to boost the voltage then respect the maximum power rating. So if it can be turned all the way up to 240V then you can only take 1A. This isn't really an issue for those of us in 230V countries but may be important in the US etc.

It would help if you tell us what's on the rating plate, or even a model number.

[vortalexfan]

Originally Posted by ppppenguin

I don't know about this specific model but there's a rule for all variacs. The maximum rating is the specified current. That's true at all voltages. I'll give an example for 120V countries. You have a 240 watt variac, so the plate will say 240W, 2A. If you set it to give 60V output, the maximum current is still 2A. Not 4A. If you take too much current you will burn the carbon brush and possibly damage the windings.

If it allows you to boost the voltage then respect the maximum power rating. So if it can be turned all the way up to 240V then you can only take 1A. This isn't really an issue for those of us in 230V countries but may be important in the US etc.

It would help if you tell us what's on the rating plate, or even a model number.

It's a Model IT-1, and it has two different wattage ratings given on the unit. 100 and 200 watts. Unfortunately there isn't a manual for this unit online just a schematic and that's it.

[Electronic M]

Originally Posted by ppppenguin

I don't know about this specific model but there's a rule for all variacs. The maximum rating is the specified current. That's true at all voltages. I'll give an example for 120V countries. You have a 240 watt variac, so the plate will say 240W, 2A. If you set it to give 60V output, the maximum current is still 2A. Not 4A. If you take too much current you will burn the carbon brush and possibly damage the windings.

If it allows you to boost the voltage then respect the maximum power rating. So if it can be turned all the way up to 240V then you can only take 1A. This isn't really an issue for those of us in 230V countries but may be important in the US etc.

It would help if you tell us what's on the rating plate, or even a model number.

I haven't seen any variacs in the US designed to take 120V in and put out more than 150V. Typically if you want 240V here you either connect to a 240V large appliance outlet or use a dedicated 120V-240V step up followed by a 240V in, 0-260V out Variac.

[jr_tech]

The 100 watt rating is for continuous duty, with intermittent use uo to 200 watts permitted, according to this reference:

https://www.w6ze.org/Heathkit/Heathkit_018_IT1.pdf

jt

[vortalexfan]

Originally Posted by jr_tech

The 100 watt rating is for continuous duty, with intermittent use uo to 200 watts permitted, according to this reference:

https://www.w6ze.org/Heathkit/Heathkit_018_IT1.pdf

jt

Ok, well it seems that this would be more than ample for use with old series string radios...

[Opcom]

Note that it is not a full range 0-120VAC variac such as might be used for reforming electrolytics, but is intended for adjusting the line voltage to match the requirement of equipment being tested/aligned as per the equipment manual specification for such activity.

The Heathkit IT-1 has an output range of 90-130V.

It will be fine for operating 115 or 117V equipment from a more modern AC line voltage of 120-125V.