100kW induction heater with a Siemens RS3020CJ Tube from 1973

[CelsoSC]

Hello, was asked to take a look at an Induction Heater that it's older than me.
It is a 100kW induction heater with a Siemens RS3020CJ Tube from 1973.

I don't have any background in Thermionic vacuum tube technologies and the few useful pieces of information I found still don't give me insight into how this device works.

How does this Induction Heater start to self-oscillate?
What is the purpose of the transformer (PN#13572) feeding a DC Voltage to the reactances (PN#13283)?
How to be sure that the Tube is defective?

I would be thankful for any help I could have to understand this kind of induction heater.

 

[electricuwe]

Hi CelsoSC,

comparing the data you provide with the schematic shows some inconsistencies in regard to power rating and tube used. 100 KW vs. 50 kW and RS3020CJ vs. RS3060CJ.

Nevertheless the question can be answered as follows: The transformer PN#13572 steps up the voltage to several kV to provide anode voltage to the vacuum tube via a rectifer.

However prior to invest in repair of such equipment, I recommend to check if replacment (or rebuilt) tubes are still available.

 

[CelsoSC]

Hi electricuwe,
You are right, I was searching for tube information a saw some RS3020, maybe that's why the reference stayed in my mind.
The induction heater has an RS3060CJ Tube.
I think that the transformer PN#13572 has a 30V secondary and can't be the kV step-up. That is done by transformer PN#14231.


Can it be that the transformer (PN#13572) feeding DC Voltage to the reactances (PN#13283) is a magnetic amplifier?

 

[electricuwe]

Yes, you are right. Anode voltage is provided by another rectifier. The reactances might a magnetic amplifier /transductor maybe for power control. But I do not see where the output is connected beside the meter.

 

[CelsoSC]

Hi electricuwe, the same line that goes up to the meter is the same that goes down to the reactances.

 

[electricuwe]

So the reactances could be a magnetic amplifier for power control as one of their further connections are going to the main transformer.