stepper motor to push open throttles

Yves · Post by **Yves** » Wed Mar 29, 2017 9:18 am

Does anyone know of a suitable stepper motor to open the throttles at idle? Need a pretty strong one.

Thanks

billr · Post by **billr** » Wed Mar 29, 2017 9:35 am

How much push force do you need? How much speed of the stroke? Both will depend on the length of the throttle lever it will push on.

Yves · Post by **Yves** » Wed Mar 29, 2017 10:38 am

Need to measure it somehow, force is doable, but speed ? It's for idle control, so not very fast.

billr · Post by **billr** » Wed Mar 29, 2017 10:43 am

Oh, also tell what total stroke on the actuator you think you need.

Yves · Post by **Yves** » Wed Mar 29, 2017 11:14 am

20 mm will suffice.

ashford · Post by **ashford** » Wed Mar 29, 2017 4:33 pm

ford eecIII systems used this. think early to mid 80's ford tbi
http://www.rockauto.com/en/catalog/ford ... valve,6072

slow_hemi6 · Post by **slow_hemi6** » Wed Mar 29, 2017 4:46 pm

Yes Aussie EA ford falcon CFI had one. Fairly large and rather ugly. Difficult to source as they were only produced in small numbers compared to mpfi.

2017-03-30 10.04.33.jpg

Yves · Post by **Yves** » Thu Mar 30, 2017 2:34 am

Is that a stepper or is that just a throttle stop ? Otherwise this would be a great option.

slow_hemi6 · Post by **slow_hemi6** » Thu Mar 30, 2017 3:31 am

It is a stepper. The photo I posted shows the rod in retracted position in one and extended on the other.

Yves · Post by **Yves** » Thu Mar 30, 2017 6:54 am

Thanks !!!

Yves · Post by **Yves** » Tue Apr 11, 2017 11:10 am

Any idea how many amps that stepper needs ?

AlanJ · Post by **AlanJ** » Tue Apr 11, 2017 12:27 pm

Another option, cruse control module from a first gen dodge. it is a PWM valve powered by vacuum. the PWM signal determines how much the cable is pulled. The module has a wide range and is very strong pulling. (I use it to control a cut-out by mega squirt). it Fails in the closed position as well. Safety first.....

Matt Cramer · Post by **Matt Cramer** » Tue Apr 11, 2017 12:43 pm

I'm pretty sure the Ford device is a DC servo, not a stepper.

Yves · Post by **Yves** » Tue Apr 11, 2017 12:54 pm

Matt Cramer wrote:I'm pretty sure the Ford device is a DC servo, not a stepper.

That would surprise me. A servo normally is much larger as it has a position feedback.

slow_hemi6 · Post by **slow_hemi6** » Tue Apr 11, 2017 6:12 pm

Matt Cramer wrote:I'm pretty sure the Ford device is a DC servo, not a stepper.

Na I have temporarily run one from my own stand alone stepper controller and just bench testing. Belled out the coils to find correct connection. I ran 2 of the 2bbl (aussie) a la side draft webbers for a little while. I did not have the real estate to use the idle control but as I had them I had a play. Definitely could extend and retract. No idea on what they pulled for current or how long they last or accuracy, just confirmed they worked. As I said before they are rare parts over here.
Just checked it has 2 coils, 30ohm each.

Yves · Post by **Yves** » Tue Apr 11, 2017 11:04 pm

Slowhemi, can you tell me what the connection is?

Assuming 30 ohm and 12V feed, would mean it would draw 30/12 = 2,5A. (motor is 12 X 2,5 = 30W) When the MS3X board only allows 0,5A this will cause a problem. Not sure how to get around that. Relays between each wire maybe ?

BTW : the part can be easily had on ebay. Of course with shipping and everything else it becomes rather expensive. Got it here in the mean time. I noticed the rather thick wiring attached to it, so that's why I questioned the current draw. It seems that I was right to question this. Didn't think of measuring reistance myself. Thanks for that.

slow_hemi6 · Post by **slow_hemi6** » Wed Apr 12, 2017 2:47 am

The manual shows the GM type steppers as having a nominal resistance of 35 to 45 ohm so these are not a lot different. DC resistance measurement is not a true indication of coil current but it is indicative. Your math is a bit off. Ohms law is V=IR and I=V/R so that's 12/30 which is 0.4A. Watts= VA so 12x0.4= 4.8W
On my motor one coil is Black/Grey and Grey the other coil is Black and Grey/Black.

slow_hemi6 · Post by **slow_hemi6** » Wed Apr 12, 2017 5:44 am

Well turns out the motor I have is faulty. I opened the thing up and it it is not actually a stepper motor, it is a simple dc motor. Black and Grey/Black is a switch that opens if too much pressure is on the actuator and Black/Grey and Grey run the motor but the motor has limit switches for max and minimum extension. Really have to apologize for the bum steer about it being a stepper.

Yves · Post by **Yves** » Wed Apr 12, 2017 8:57 am

slow_hemi6 wrote:Well turns out the motor I have is faulty. I opened the thing up and it it is not actually a stepper motor, it is a simple dc motor. Black and Grey/Black is a switch that opens if too much pressure is on the actuator and Black/Grey and Grey run the motor but the motor has limit switches for max and minimum extension. Really have to apologize for the bum steer about it being a stepper.

Correct on the amps and power. My fault

I have different colors on the one I have here : black, red, yellow and purple.

So basically it's just a throttle stop then ? d***

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stepper motor to push open throttles

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