Ignitron equvalent & Induction furnace Converters

[vivekgupta999]

We have old Induction Furnace (Make KORF)of 2ton. It is having static frequency converter of 1300Kw with input of 700V & 50 Hz & output is variable voltage & maximum frequency of 500Hz. In frequency converter there is one pre current device which is having Ignitron (Mercury arch rectifier) to give starting energy to Capacitor & Inductor. Can anybody through the light on pre current device? How it works? Ignitron(English electric valve Co.,BK484/55524) is bad. Can anybody suggest for its equivalent device as they are no longer available in market?

 

[Skogsgurra]

It is quite often possible to use a thyristor instead of the thyratron. The action is similar and the thyratron was used before thyristors became available. It is often possible to modify the gating circuit (using a transformer, a few resistors and diodes) so that you can be up and running after only a day or two.

The precharge circuit either uses a transformer and rectifier (only if the precharge is used when starting the inverter) or a series resonant circuit with a thyristor in it (if the precharge is used every cycle).

Do you have ant drawings available? We may be able to help if we knew more about the circuit.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[sreid]

Is this device simply a Mercury Arc Rectifier for converting AC to DC?

 

[sreid]

Oops, forgot a link.

http://en.wikipedia.org/wiki/Mercury_arc_rectifier

 

[bill1055]

Or... If you want to stay with the tube, these folks may have a replacement.

http://industrial.rell.com/