Starturn 8

[Spike]

Any Starturn 8 users out there, experiencing tool-changer problems? It seems that when the toolpost reverses against the detent, the motor is still under (reduced) power, which eventually results in damage to the primary tufnol gear in the motor gearbox. Mine is currently on its fourth gearbox.

Does anyone have an electrical circuit diagram that I might beg/borrow/copy?

Also, I recently blew the main input fuse due to spindle overload. (Took me an hour to locate it - cunningly concealed in the 3-pin socket at the rear of the machine). This was replaced, and all other external fuses checked, but still no motor rotation, nor X Z movement.

Any ideas? Thanks in advance.

Spike

[Denford Admin]

This sounds a lot like an older version of what we have now-

Is the motor/gearbox a little 1 inch diam motor with the first one or two output gears being made of hard plastic stuff , and the rest are metal ?
It also has a black heatsink cap over it - which gets very hot ?

If it is, then this is a larger (both motor and gearbox) version of whats used on our current NovaTurn - this problem has been addressed in the newer turrets by altering the gearing - we think that the turret was made to run slower.
When the turret is holding in reverse, the motor is supplied half-wave rectified 24VDC, this caused oscillation which eventually wears out the gears - running forward is full-wave rectified, but this would be too much for the motor to hold constantly

Just a thought, but you could look into some way to change the frequency of the holding voltage - PIC/PWM chip and solid state relay ? In order to stop the osscilation - We tried smoothing the half-wave with capacitors without success - as that would mean the holding torque would be higher.

Hope these rambling help put you in the right direction

We probably have the electrical and mechanical drawings somewhere, but it would cost us time and money to get hold of them

[Spike]

Thanks for the speedy response.
Yes, the motor is as you describe, and the heat sink does get quite hot, although not excessively so. I had deduced that the holding voltage was reverse polarity/half-wave ac, and was thinking about some sort of relay device which cut-in after a suitable delay (to allow the turret time to park) and then reduce the holding current to a minimum - which is why I am anxious to obtain electrical info. Even a description of the various boards and their layout would be a start.

[Denford Admin]

Let us know the type of controller - GSM / North East electronics / Baldor and any other stuff that may be relevant as I (or anyone on the Forum) wouldn't even know what to look for otherwise.
Whats it controlled with BBC - PC ?

Email me photos if you can
email: technical@denford.co.uk