Test rig is mk3 heater box - test car is mk3.

Mac.

Ok, in which case, I wonder if either the motor in yours has been cleaned and serviced to MacSpec and is becoming tired in the test car (maybe the reason the pack tripped wasn't a shagged bi mettallic to start with, but got knackered with actuations?) or, if the air path is suitably restrictive that the motor is feeling a restriction and showing this in an increased current draw. I noticed when I fitted the lotus 7 rad fan to my system that it had huge airflow in the lounge on its own, but was notably down when mounted in the car.

Does the guinea pig have nouse/gear to current test their own motor in situ? I'd not recommend a normal multimeter, most are fused at 10A, but maplins do a fairly useful thing N48CY, it has 1/4" spades on it so it'd be super easy with 1 extra wire for them to put in to test.

However it works Ok in 1 or 2 and only cuts out in 3. Current draw will be less in 3 (no resistors to run through) and the airflow should be greater due to the higher fan speed. By all accounts Position 3 should be the one with the least potential for overheating.

As Pos 3 is fed separately from a relay is it not possible that it's the relay that's tripping out and not the new MacPack? Wasn't the original pack bodged to start with? If so maybe the guinea pig's car could be at fault and not the MacPack. If the relay in the car is faulty the previous owner could have bodged the pack to get it work on all three speeds eventually causing the pack to fail.

Just a thought...

Just to confirm since I'm the guinea pig and there's a few assumptions being made here....

- The car is cold, its in a garage, it hasn't been run
- The cutout operates after about 5-10 seconds on position 3, and will then restart after a couple of seconds once turning off and back on. You can hear the pack click?
- Haven't managed to get it to cut out in position 1 yet

Have a cheapo multimeter if that helps to get to the bottom of it, but wont have any time to test til next weekend. Failing that Chris - bring yer stuff along to the BKV.

Why do Volvo make it such a pain to remove the heater box?! Prior to the pack failing the fan operated perfectly on all speeds for about 6 months in my ownership.

Edit: adjusted post. Ran fan on pos 2 for 15mins, seems fine but will almost instantly cut out when switching to 3 from 2

UPDATE

The fog is clearing - I have now duplicated (as far as is possible) the conditions of the test car in which my rebuilt pack failed and it performs exactly as Steve describes! There is also an obvious answer and further questions.

I have spent some time gathering data and will (when I've ad a cuppa) post it. Very briefly there are two versions of the post 86 heater motor one of which draws much more current - needless to say all my rig testing used the lower rated version.

Mac.

SteveP wrote: Why do Volvo make it such a pain to remove the heater box?!

300-series is easy. 200-series on the other hand... The whole car is designed around the heater box.


-Marko

Ok girls - today's data.

The motor from my Redline (heater box/motor used as test rig) is a :-

Delco H-A1 9341/01

Speed1 momentary 6A runs @ 2A pack temp 42c
Speed1 momentary 10A runs @ 4A pack temp 18c
Speed1 momentary 15A runs @ 6A pack temp 16c

The motor from my 1.4 3door is a :-

Delco 504864081\077-7

Speed1 momentary 6A runs @ 3.5A pack temp 58c. With thermocouple on bi-metallic frame 34c.
Speed1 momentary 14A runs @ 7.5A pack temp 35c. With thermocouple on bi-metallic frame 38c.
Speed1 momentary 19A runs @ 15.5A pack temp 20c. With thermocouple on bi-metallic frame cut out @ 43c.

In theory the cut out I have used should be ok - BUT with it operating at 43c I now have to question if my bay sourced "otters" are rejects, or indeed fakes. I need to get my head around what my selected rating of 92c actually means - I assume that is the temp the switch trips at - but measuring the temp of the actual mechanism gives a 43c actuation. DOH !
I shall speak to Otter and see what they say.

The two motor versions



Motor from Redline (test motor)



Motor from 1.4 3door (and I assume type Steve has)



Vent pipe of test motor



Vent pipe of 1.4 motor



My next check will be to hold the cutout contacts closed and see what the max temp reached is in full and reduced airflow and spec the cutout accordingly. It does seem however that the c/outs I have acquired are tripping way too low.

Playing will continue. There, see how simple that was!

Mac.

Hmmm interesting... never straight forward is it!! To throw a spanner in the works my motor is actually your redline motor style, not the 3 door one.

Good sourcing Mac.

Want me to have a look through the electornics suppliers I use and see if they supplier Otters? They will be genuine at least.

Second thought as I see it, RJ, this cooling hose is knackered in 4 out of 5 cars I see over here, any plans for it on the list?

Hi Steve, I lurrrrrv spanners - plainly there is a huge difference in motors of ostensibly the same type.

Chris - I'm talking to Otter already to see if they can explain why "my" G6s are cutting out so low.

This morning I clamped a cutout shut and attached a thermocouple (yes I checked that there was no resistance through the switch both from the packet and installed in a pack). This give true switch temp.

Results,

3door motor
Speed 1 Full air 26c. No air 39c.
Speed 1 Full air 36c. No air 71c.
Speed 1 Full air 61c. No air 162c.

Redline motor
Speed 1 Full air 24c. No air 33c.
Speed 1 Full air 30c. No air 45c.
Speed 1 Full air 36c. No air 63c.

I tested the original 3door pack and 3 rebuilt packs - all gave results within a degree or so. (at least we're getting an idea of the environment these packs live in.

Ps. Otter were verrrry surprised that the " original" G6s had no covers (should always have cover). I wunnnnnder if the original supplier found " their" rating was a little marginal and removed the covers to gain a little more cooling effect.

Jeeze, I hate these simple solutions to simple problems!

Mac.

Never had considered that one to be a candidate, didn't even know that there was one ...

Interesting, I wonder if there is another resistor somewhere in the higher current one. Alternatively it maybe that the cooler one does not need the thermal cutout but it was left in, because they didn't have time to retest and it wasn't going to save any real money.

Kids this is real Engineering, just one little component.

Ride_on wrote:Interesting, I wonder if there is another resistor somewhere in the higher current one.

Only one part number listed

Gets more odd the day!

One part no., two different motors, two different fans, two different cooling pipes, two different wiring connectors, and the front casing of the heater boxes are different according to the motor type (cooling pipe stub v hole).

The idea that the motor was changed but cutout left in is a logical suggestion - but Steve reports "his" motor is of my test type so should be "lower current draw" - it isn't! The "additional resistor, again is logical but if it exists it should be in the motor itself (for the difference to show on my test rig) but dismantling "my" higher current motor shows no sign. If it's in the motor windings why the huge difference in motors of the same type ?

Do we have a failure mode of the motors (both types) producing this effect - today I shall carefully look at my high current example for resistance across the brushes and will measure the torque req'd to turn the armature. (the bushes don't seem tight but you can never tell with those self aligning types).

Mac.

After reading this I don't see why someone hasn't mentioned using a pulse width modulation PWM controller with 2 fixed/variable resistors selected by the blower switch.