Heater dissecting, no what ?

[Poppe]

I took the heater apart to see if I could fix it.
Heres whats inside for you who has not done this operation:





If I measure the input resistance on the orange HV wires I find its about 700 Ohms, obviously too high.
Inside there are two heater elements both measuring about 12 Ohms which seems to be OK.

All cables are going in to the yellow plastics at the bottom of the heater and I figure there is something inside there which has gone wrong. The 10.000 dollar question is whats inside the plastic ?

Anybody knows ?

[Warlock]

It's a fuse in the yellow resin which probably has blown, unfortunately it's very hard to drill it out...
I've seen pictures of it in this forum, and I'll try to find the right thread for you...

Edit: http://elbilforum.no/forum/index.php/topic,3773.msg61453.html#msg61453

[Poppe]

Thanks Warlock for your input.
I tried to read the whole thread and that took a while.

If I understand everything correctly I should measure the HV power where the heater is connected. If I measure 370V there the fault must be in the heater itself and then its likely that it is the big fuse that has left the building.

[Warlock]

Yes

Unfortunately, if you have a gen2 CPU (oval to square plug), the plug must be connected, or the interlock will disable the car, and the HW system. You might need to use probes or something...

[Poppe]

Fortunatly I have a gen1 CPU.

I'm I correct to understand that if I had had a Gen2 the connector to the heater would have had 4 wires ? Two for the HV +/- and two for diagnostics to check the connector is in place ?

My plug is round and has only two wires.

[Warlock]

Partly correct.
It would still only have 2 wires out of it, but have in addittion to the two thicker pins to connect to the HW outlet, have two much smaller pins (which is shorted inside the connector) for the interlock...

If you have a round connector, you have a gen0 or gen1 CPU

[Poppe]

hma wrote i the other thread:

Før man kjøper en slik må man måle om "power current elevatoren" (kortslutningskretsløpet) er permanent kortsluttet.
Det kan man gjøre ved å måle motstand mellom HV- og halvledersikringen.

Unfortunatly he does not mention what the result of the measurement should be

I managed to work myself into the yellow polyuerathane (?) which was quite easy with the help of a heatgun and a screwdriver. Mustn't heat to much though since the PU, if it is, gives off toxic fumes when too hot (smoking).

Anyway, from HV+ I have zero resistance to either side of the big fuse. Not sure if this is good or not ?
Have not been able to check the HV yet since the Think has only been at home in the dark.

[Warlock]

since this is a semi-conducting fuse it should only conduct in one direction. Maybe your multimeter has diode-test function?

[BauDemo]

since this is a semi-conducting fuse it should only conduct in one direction. Maybe your multimeter has diode-test function?

I have never heard of such fuses - Do you happen to have a link to a such semiconducting fuse?

[Poppe]

Here's a link to a seller of the fuse:
http://www.highpowersemiconductors.com/product-detail.aspx?productID=2573
As can be seen printed on the fuse there is a fuse and a diode in series but how do I know which end is which ?

Just noticed: On the page linked above you can see "Polarity: N/A "
How can that be when a diode is involved ?

Found a tech spec:
http://www.farnell.com/datasheets/1468450.pdf

[Poppe]

I measured it today with a diode test multimeter and the resistance is exactly zero Ohms in iether direction. Cant figure out if this is good or bad or what the reading should have been.
As far as I can see from the spec pdf there is no mentioning of any diode functionality.

[Warlock]

Hmm

In that case i must apologize.
I went with the schematics drawn upon it (under the bussman logo) it is clearly drawn a fuse and a diode It also made some sense in the general schematics in the other tread.

Anyway, if the fuse conducts it's at least not blown...
What hma is refering to is the heaters self safety feature, and this fuse should be a part of it.
When my girlfriends heater was in question i measured the HW output to ground, and found the negative line with some voltage, but partly floating. The positive line had no voltage (the PCU fuse was blown...)
The heater turned out to work tho. I Also Megged the unit, made sure it had no shortages towards ground. And after I had changed the PCU fuse to 25A everything worked as it should... And still do, knock on wood...

I do believe hma mentions in another tread what you could expect when you measure the heater.
I'll have a look for that to...

[Warlock]

Ok

In this tread: http://elbilforum.no/forum/index.php/topic,11973.msg174342.html
I've noted that i measured the fuse and there shoud e a diode there somewhere...
("1. Målte halvledersikringen i varmeren, 0.4V drop over dioden i lederetningen, og uendelig motstand i motsatt retning.")
I don't remember opening the heater tho, just measuring on the leads out of it, hmm...

[Poppe]

It wont even help to open the heater you have to carv the fuse out to access the terminals. Dont think you would forget that.

[Warlock]

I know
So: No, I defiantly didn't do that
I messed around with it for a hole afternoon tho, so i might have come up with a nasty trick.

But this means you could measure (some of) the safety circuit from the HW-leads and the ground-wire.
I've been trying to fin the Mes-Dea manual i once found with a schematic in it explaining the circuitry, unfortunately, I haven't been lucky so far...