EZGO Electric Tachometer

[INWO]

Duplicate post........................

[rbuggies48IN]

Johnnieb

Yes it was! That is an old picture. I now have a digital volt meter with blue numbers.

[TerryH]

Interesting. I use that same little shift light tach, Johnnie. Works perfect for us. The Zilla has a tach drive output so super simple installation on the dragster.



Here's the speed sensor setup on the motor...

[kgsc]

Okay I know this a fairly old thread but.. Could a speed sensor be added to a series motor?

[TerryH]

Originally Posted by kgsc

Okay I know this a fairly old thread but.. Could a speed sensor be added to a series motor?

Yes. That's what we do in the dragster. Not sure if a normal series controller is set up for speed input though.

[kgsc]

Terry I just meant if some crazy person wants to add a tach to a series cart.. Oh wait

[TerryH]

Originally Posted by kgsc

Terry I just meant if some crazy person wants to add a tach to a series cart.. Oh wait

Guilty.

[Volt_Ampere]

I would always use an optical coupler for this application like you did. That isolates your electronics from the controller electronics. Most optical couplers would have no problem with motor tach frequencies. JohnnieB I think your math is off by a factor of 60. Most encoders put out 4X motor RPM so at 6994 RPM, you would have 6994 * 4 / 60 or 466.27 PPS.

[INWO]

Looks like the kit will use an aux. hall effect in stead of optic isolation.
No chance of messing up controller tach.

A lot of motors use these.
Mine would have two sensors in one cap.

[JohnnieB]

Originally Posted by rbuggies48IN

Johnnieb

Yes it was! That is an old picture. I now have a digital volt meter with blue numbers.

Thank Goodness. My DTS gets upset when her bling is used in undignified manners.

Originally Posted by TerryH

Interesting. I use that same little shift light tach, Johnnie. Works perfect for us. The Zilla has a tach drive output so super simple installation on the dragster.

I stole the idea from you.

After using the tach function on my DVM, I was pretty sure a tach for a V8 (4 pulses per crankshaft revolution) would work and was trying to figure out what to buy when I saw a picture of your dragster with a SW Ultra Shift Light installed.

I got it working, but was still figuring out where and how to install it when Alltrax came out with their XCT controller, which uses the speed sensor and logs motor RPM in the data log, so I had to rethink things since the pulse train from the speed sensor would be used by more than one electrical circuit and it went on the back burner.

However, seeing this old thread resurrected has gotten me thinking about it again.

Since the XCT controller powers the motor's speed sensor circuit, the tach display either has to be powered by the controller's speed sensor circuit, or electrically isolated from it. Sharing a common negative and optically isolating the signal to the tach display will work, but I'm also looking into powering the tach display with an isolated DC to DC converter. (IE: Murata MER1S1212SC)

I'll probably end up installing the SW tach for real time motor RPM and a Divide-by-N counter to give me real-time speed.

Originally Posted by Volt_Ampere

I would always use an optical coupler for this application like you did. That isolates your electronics from the controller electronics. Most optical couplers would have no problem with motor tach frequencies. JohnnieB I think your math is off by a factor of 60. Most encoders put out 4X motor RPM so at 6994 RPM, you would have 6994 * 4 / 60 or 466.27 PPS.

Oops! You are correct, I posted PPM instead of PPS.

Thanks for the catch.