openinverter forum

I've bought a GS450H transmission. It has a replacement connector for the VSS (I think that's what it is).

Can anyone confirm the colour of their wires /pinot for the connector pictured? thanks.

I believe the one with the red dot (pink?) is positive but it's been some time since I worked on this bit. If you spin the transmission up, you can read the voltage off the leads (AC if I remember correctly).

VR sensor, no polarity.

xp677 wrote: ↑Wed Nov 29, 2023 7:55 pm VR sensor, no polarity.

I don't mean to be pedantic. VR sensors do have polarity. It just might not matter in this case.

Some setups (maybe not this case) can see a trigger go by but the sine wave going negative first instead of positive may cause it to throw an error code.

If it's watching the wrong zero cross (flipped polarity) the tooth to signal time drifts (longer delay as rpm increases) as rpm increases. If it's only speed signal it might not matter at all.

thanks both, I got around to doing some testing expecting to see varying voltage on this when spinning the motor but didn't see anything unless I set the multimeter very low on the DC setting. I set it to AC volts and it gave me a reading of 1V, is this right?

Yes, vr sensors are ac and at slow speeds it's a very low voltage.

jrbe wrote: ↑Fri Jan 19, 2024 9:38 pm Yes, vr sensors are ac and at slow speeds it's a very low voltage.

Thanks, any idea what I can expect at max rpm from it?

Jacobsmess wrote: ↑Sat Jan 20, 2024 7:59 am Thanks, any idea what I can expect at max rpm from it?

Depends on the sensor and gap. Off the top of my head 60-80v is what I remember from many years ago for max voltage at a small gap and max rpm.

Jacobsmess wrote: ↑Sat Jan 20, 2024 7:59 am Thanks, any idea what I can expect at max rpm from it?

It is connected to the GS450H inverter right, so becareful you do not alter the wave form by how you are measuring it as it might cause issues.

Best to do some test with a scope at low speeds to see how many teeth the pick up is.

Thanks Tom, it's 15 teeth. It's not connected to the inverter at all in normal application I think.

So I ran it today and watched mg2 and mg1 rpm and it didn't exceed 1Vac at 1000rpm. Would this relationship be expected to be linear? (Max mg2 rpm of 10000=10Vac) or is it not as simple as that?

Nope, it is a shape for a wave that you read the voltage from that changes frequency

https://mcs.woodward.com/content/motoha ... acing.html
https://forum.arduino.cc/t/how-to-read- ... ter/153980

You need to figure out how to read it properly for it to be useful, easier just to read out MG1 and MG2 speeds from the Zombie.

AC gets a bit funny when assigning a voltage. It's RMS voltage but there are gaps of no signal / no voltage typically with these trigger setups to mess with the value. The peak voltage will be a lot higher than what a typical AC meter will display. You'd see this better on an oscilloscope.

Yes the voltage should increase with rpm but it may not be linear.

Some vr sensors are under a volt at low rpm. Yours is where I'd expect a vr sensor would read on a typical RMS AC meter but I don't know exactly what the gs450 one is typically.

a simple and safe way to read a VR sensor is to use a MAX9926.

https://www.analog.com/media/en/technic ... ax9927.pdf