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Thyristor Cross Reference


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#1 gerryroxas

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Posted 08 April 2006 - 02:49 AM

Hi,

I'm looking for a Cross Reference of obsolete high power SCR.This is manufactured by HITACHI: Type CJ02Y

I do not have a data sheet for this SCR except the following information:

C: Thyristor
J : 200 Amps rated current
02: Supplier process code
Y : 1400 volts

I intend to replace it with any other brand available in the market, unfortunately I can not compare some important specifications such as the "gate" current and voltage requirement to fire the SCR.

I will appreciate your kind assistance and its a great pleasure to know somebody out there who is willing to share their knowledge and expertise.

Best regards,

Moises

#2 jraef

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Posted 08 April 2006 - 09:46 PM

Try these folks. Very knowledgeable about the entire industry.
http://www.westcode.com/
"He's not dead, he's just pinin' for the fjords!"

#3 marke

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Posted 08 April 2006 - 10:28 PM

Hello gerryroxas

I have been unable to locate good information on this device, but it is rare for there to be a significant variation in the gating requirements for similar sized SCRs. Having said that, if you can use devices with gate voltage of 3 volts or less and gate currents of 150mA or less, you should be OK.
The gating characteristics are not critical provided that there is enough. You would be very unlucky to destroy the device with excess gate current in an existing design.

If this is in a phase control environment, then one of the most important parameters is the power dissipated at the rated load. There are large differences between the losses in SCRs of similar ratings and sizes. If you replace a good SCR with a lossy one without increasing the heatsink, you will have overtemperature problems. I would look for an SCR with a low voltage drop at rated current. target someting in the order of 1 - 1.2 volts at rated current rather than 1.5 volts at rated current.

If the SCR is not in a phase controlled environment, then there can be a raft of other parameters that are critical such as turn ON time, turn OFF time di/dt etc.

How much information do you have on the application??

Best regards,

#4 gerryroxas

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Posted 11 April 2006 - 04:57 AM

Hi Marke,Jraef

Thanks a lot for technical assistance you have provided.

The said SCR, Hitachi CJ02Y, was employed for 4 quadrant control of 2-125Kw DC Hoist motor of old Ward Leonard Static Drive.

I have few pieces of old (used) SCR of this type ( never mentioned if this is still in good condition). After doing some bench testing.I found out that gate voltage and current is about 1.02-1.1 volts, 42-46mA respectively.This is a stud (threaded ISO M24X1.25) type Thyristor.

With respect to that measured values, Can I use other SCR with gating requirement of 3 volts,200 mA? Is 2 volts and 100's mA will make a difference in SCR behavior?

In Testing for Failed SCR, Aside for Shorted and Opened, is the gate sensitivity a common failure too?


Thank you for your time and effort in considering my queries.

Best regards,

gerryroxas

#5 marke

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Posted 11 April 2006 - 05:25 AM

Hello gerryroxas

There is a wide range of gating energy required for a particular type of SCR. The gate voltage and current that are quoted are the minimum voltage at which the manufacturer will guarantee that all SCRs will trigger, and the gate current is the minimum current that the manufacturer wiil guaratnee that all SCRs will trigger.
If you do individual tests, you will generally find that the voltage and current for a particular SCR will be well below this figures.
The maximum limits of V and I are much higher and it is actually gate power that is the issue.
In terms of replacement, provided that the circuit is producing a high enough voltage and current to properly trigger the SCR, there will be no problem. I would expect that the trigger circuit would be designed to provide more than 3 volts at 150 - 200 mA so it should not be an issue. one way to find out, try it and see!!

If the gate current is low, there may be switch ON issues or there may be di/dt issues. If you are not switching into a capacitive load, di/dt should not be a major concern.

Occasionally, you can find SCRs with gate problems, but this is very rare. Invariabley, the problem is anode - cathode short circuit. The gate issues that I have seen have generally been intermittant gates on Hocky puck SCRs where the gate spring (internal) was not strong enough.

Best regards,




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