Reading phev motor temps

[FFMan]

Whilst trying to sort out paperwork etc turning my attention to the little things.

In this instance connecting the temp sensors from the phev rear motor to the inverter.

The motor has two sensors, the pairs of wires read 13.45 ohms and 13.28 ohms, so near enough to each other to be plausible.

I've wired pins 22 & 23 of the ampseal to my junction box to make them accessible. Under advice i wired a sensor groudn to ground and the other side of the sensor to one of the input. Tried both with and without a 1k pull-down from input to ground as advised. On the ampseal pin 29, 21,11 & 17 are all wired to a common ground.

My values reported via can agree with the web interface (so i don't think it's a can or decode issue), one is constant -40, the other fluctuates a little around 88.

Given i think the temp inputs to the ampseal are adc inputs, and i think the motor sensors are thermistors i expected a pullup somewhere but this is based on a limited understanding of how this should work.

Have i gone wrong here somewhere ?

[Bigpie]

There's only one input, it's missing part of the resistor divider that gets the voltage right for the stm32. One side connects to the 5v output, the other to the input, with the resistor divider.
Give me a call if you need to.

So T1 to one side and T2 to the other, and T2 to gnd via the new resistor to form a voltage divider.

[Pete9008]

That doesn't sound right, the measured values seem way too low.

Just checked on my motor and read 15k on both sensors which is more the kind of value I would expect.

For reference the resolver measures around 36R on the exciter and 77R and 80R on the sin/cos outputs.

Pull down doesn't sound right either but would need to dig out the circuit diagram to check whether there is already a pullup on the board.

Edit - just seen Bigpie's reply and agree with that.

[FFMan]

> There's only one input,

and is that pin 22 or pin 23 on the ampseal connector do you know. Is the other one NC ?

> So T1 to one side and T2 to the other, and T2 to gnd via the new resistor to form a voltage divider.

T1 to 5v out (ampseal 14), T2 to one of pin 22 or 23, and 1k resistor to ground.

thanks

[Bigpie]

23 on the IDC should be the 5v to one side of the sensor and then 24 the other side of it, and it needs the 1k resistor to ground, either internally or externally.

These are the ampseal pins

[FFMan]

thank you - for some reason i had assumed there were two inputs. i think in my documentation i summarised the labelling and mis-lead myself.

this makes perfect sense thank you

[FFMan]

ok- i'm still getting -40c showig so i guess somewhere along the line, the input got fried. I guess i can interface the temp sensors to my arduino instead. does the inverter use the motor temp figure ?

My temphs still shows approx 85 though it does vary a bit with ambient - should this be degrees C ?

[FFMan]

> The motor has two sensors, the pairs of wires read 13.45 ohms and 13.28 ohms, so near enough to each other to be plausible

helps if i note what scale i put the meter on, those are kohms numbers. Does this likely make them 15k @ 25c maybe for calibration purposes to arduino or are they unlikely to be a standard part ?

[Bigpie]

I think my motor is 50k at 25c from memory.

15k sounds more plausible than 13 ohms.

[arber333]

> The motor has two sensors, the pairs of wires read 13.45 ohms and 13.28 ohms, so near enough to each other to be plausible

Could be that motor has additional thermal switch to open connection when at high temp. 13ohm seems a lot like transistor output.