On 01/20/2017 08:27 PM, Jan Steinman via EV wrote:
From: Jay Summet via EV <[email protected]>
I tested one of my original Curtis 1231C didoes, as well as one of
the replacement diodes I bought to replace them ... from DIOTEC,
specifically their DR7506FR model (the R at the end means ?Reverse
Polarity?, making them an exact drop in replacement in form factor
and polarity).
I have not looked at that particular diode spec sheet, but be aware
that for this sort of service, there is more going on than simply
current and voltage drop. You also need to consider recovery time.
Big fat diodes can have a significant amount of reverse-bias
capacitance, which can cause excessive dissipation with fast
switching times. You may need to make sure your “drop in replacement”
is a “fast recovery” device. If the manufacturer’s application notes
mention “switching power supplies,” they’re probably fine, but if
they are intended for 50/60 Hz operation, maybe not.
Unfortunately, this spec is something a typical home lab isn’t
equipped for measuring. You’d need a high-frequency curve tracer,
although comparing reverse-bias capacitance may be useful.
Good point, but the DR7506FR's should be fine, as they are sold as "soft
recovery fast switching" and specifically designed for electric vehicle
motor speed controller applications.
HIGH Frequency: 250 kHz
FAST Recovery: 100nS - 150nS
You can read their spec sheet here:
http://www.diotec-usa.com/dr7500f.pdf
Jay
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