Turbo pumps

[Jerry]

Ill have to give one of my VFDs a try and see what happens.

The cable length should not matter. They make the cables that way so they can sell you a real expensive cable every time. These things dont run at a high enough frequency to worry about the effects of cable length.

Look in the manual and see if it specs anything about the cables or if it list the connector part numbers. Or just give varian tech service a call. I am sure they will tell you what you want to know. But watch out putting the control on different turbos. Who knows, they may be designed for the parameters of motors specific to one model of pump.

[Joe Jarski]

The VFD faults that I had were related to the cabling being too long and the PWM pulses being reflected back to the controller as I recall. It didn't matter what size or length I used the faults were always the same. I even tried changing the carrier frequency without any luck.

I have a V60 controller myself. I don't think that shortening the cable would cause any problems, but increasing it might.

[Chad Ramey]

On the topic of controlling an tph 055 with a l6234 chip:
I used the great google to search around the internet for a circuit that I could build a controller suitable for a pump off of the l6234. I found this article of instructables.com http://www.instructables.com/id/BLDC-Mo ... -HD-motor/ . Looks like the arduino program will need to be modified to work properly, but take a look and see if its useable.

-Chad

[Jerry]

The problem with that design is that it is intended for use with a motor with a permanent magnet rotor and hall effect sensors for feedback. The pumps here are not that.

There are several vendors of sensorless brushless drive ICs and Atmel has example circuits with code available.

[Chad Ramey]

Jerry,

Ah ha. Yes, I just began reading one of the articles the author cited and realized that. I remember some (I think it was you actually) citing the amtel chips earlier on in the discussion. I'm going to check those out and see if I can use one of their application schematics.

I've tried Alex's circuit and still haven't managed to get it working so I'm electing to try something different like an IC with digital control. So, hopefully this will work.

[Doug Coulter]

Chad, did you ever get to the point of seeing the hall signal toggle when the thing was spun manually? If not, no circuit will work. I admit, I didn't check Alex' circuit out to the point of proving to myself it would work.

[Chad Ramey]

Yeah, I was able to read the hall sensor with a scope and it seemed fine. The majority of the hold up with the circuit has been the recent discovery that I had the 7474 chip wired backwards in the circuit. I'm in the process of rebuilding the circuit with high hopes of it actually working this time.

-Chad

[Doug Coulter]

Stuff happens. If the power polarity got reversed, you might need a new chip, they really don't like that.

[Chad Ramey]

Yeah, stuff happens at a incredibely high frequency when I start dealing with electronics. Tyler gave me instructions for testing the chip so I'll be trying that out as soon as I get home from robotics team practice. Details will be posted here later tonight.

-Chad