Guru
Joined: 02/02/2017
Location: AustraliaPosts: 1432
| Posted: 06:59am 28 Oct 2018 |
All the time.
Today I put one HY4008 on a PC cpu heatsink, no fan.
I then put it on the high side supply to a spare inverter (Powerjack LF something)
with a 10 litre hot water urn as AC load.
The idea is to put about 50A DC through one HY4008.
The only load of this size I have access to is an inverter powering a large AC load.
I had to set up a camera to video this just in case we had some 'splosions.
I precharged the inverter caps via a resistor, switched on the HY4008 with 14V gate drive from the bike battery charger and ... no sparks.
I switched the inverter on and .. no sparks.
I switched the urn on and .. no sparks.
It ran fine for 6 minutes or more. In this case the heat generated from the MOSFET was conducted efficiently to the heatsink. I had the copper plate of the heat sink warmer than the front of the TO-247 case of the HY4408.
Not a lot of heat actually, maybe 15C more than ambient with no fan.
So at last I have a test that shows heat conduction to the heat sink working well.
I repeat I was concerned with this but after this test today I am happy to use
the heat sink temp as a guide to HY4008 junction temperature.
A still from the video:
wronger than a phone book full of wrong phone numbers