The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
Subject: Re: Stepper motor question
Date: Mon, 13 Jan 2003 11:58:17 -0800
Organization: Posted via Supernews, http://www.supernews.com
X-Newsreader: Microsoft Outlook Express 6.00.2800.1106
Thank you for your responses. Raising the voltage solved the problem.
"Frank Bemelman" wrote in message
> "Esoteric" schreef in bericht
> > Hello all,
> > This is my first time working with a stepper motor and related drive
> > circuitry.
> > I am using an optical encoder w/ 360 pulses/rev to generate a quadrature
> > waveforem (2 bit grey code). This signal goes through logic and a Step
> > pulse & Direction are generated as outputs. These are fed into an
> > 5804. The 5804 is set up for full step with option for one or two
> > The motor is a 6 wire unipolar motor. 12V 75ohm
> > The system works fine while turning the dial on the encoder. The issue
> > that if I turn the dial too fast the stepper motor stops rotating and
> > "buzzes" until I slow the ecoder down again. This is regardless of one
> > two phase operation on the Alegro.
> > The Alegro 5804 docs state that a minimum step input pulse width is 3us.
> > get nowhere near that with manual rotation. This condition occurs with
> > step input of around 10ms as seen on my scope. So I have ruled that
> > Is this motor resonance? What is causing this and how do I get rid of
> > I do not need extreem speed on the motor. It is being used to manually
> > control a butterfly valve on a propane fired foundry. The stepper
> > geared down such that it requires about 1000 steps to go from open to
> > closed, this was done to increase resolution on controlling the valve.
> Your motor does not develop enough torque. Try increasing the 12V to 15V,
> see if it can go a bit faster. When you go faster, the windings get
> pulses. It takes a while before the current reaches a certain level, and
> with short pulses the current drops. The result is that your torque drops
> and drops, and when too low, the motor stops. You have to find a way to
> increase the current, increasing the supply voltage is the only option.
> Beware that at low speeds the current gets larger, and a too high supply
> voltage may overheat the motor.
> Unipolar, 12V, 75ohm seems a rather small steppermotor. The UCN5804 is a
> very simple stepperdriver. What you may need is a more sophisticated
> controller with current control (pwm) and a higher voltage. Possibly also
> a motor with lower resistance windings.
> Frank Bemelman
> (remove 'x' & .invalid when sending email)
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup