2-phase AC motor drive
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Posts: 46,084
Ciao,
I'm looking for some informations or experiences about speed control on a low
voltage (28V) AC 2-phase motor (that kind of motor that uses two windings, and a
capacitor in series to one of them).
The Stamp side of my project is not the problem, but it is the drive technology:
phase-control with Triac is one solution, but it is generally said that with
inductive loads it is not very reliable at low speeds. Maybe not - I'm just
starting and I didn't try any circuit - but it is a fact that DC drives are more
popular and well known among the homebrewers! Anyway, I cannot change the motor.
If anybody experienced something for this kind of motors, I will appreciate his
help.
Alberto.
[noparse][[/noparse]Non-text portions of this message have been removed]
I'm looking for some informations or experiences about speed control on a low
voltage (28V) AC 2-phase motor (that kind of motor that uses two windings, and a
capacitor in series to one of them).
The Stamp side of my project is not the problem, but it is the drive technology:
phase-control with Triac is one solution, but it is generally said that with
inductive loads it is not very reliable at low speeds. Maybe not - I'm just
starting and I didn't try any circuit - but it is a fact that DC drives are more
popular and well known among the homebrewers! Anyway, I cannot change the motor.
If anybody experienced something for this kind of motors, I will appreciate his
help.
Alberto.
[noparse][[/noparse]Non-text portions of this message have been removed]
Comments
What happens when you try to control and AC motor with an SCR type control,
is that the motor speed tries to stay at 1800 RPM, or whatever, based on the
60 HZ line frequency, but the torque goes down due to the lower average
voltage. That's what makes lamps dim. If you're driving something like a fan
where there's a steady increase in required torque as the RPM's go up, then
it will work with an SCR controller over most of the speed range. Getting it
to run at really slow speeds would still be a problem.
Of course, you could play with frequency control, etc... but most AC motors
are "tuned" to run at 60 Hz (or 400 Hz for aircraft) and will either
overheat or get plain goofy at frequencies much outside their design norm.
How much speed range are you looking for?
Mike Sokol
Original Message
From: "Alberto Calderara" <albertocalderara@t...>
To: "Basicstamps group" <basicstamps@yahoogroups.com>
Sent: Thursday, July 10, 2003 1:10 PM
Subject: [noparse][[/noparse]basicstamps] 2-phase AC motor drive
> Ciao,
>
> I'm looking for some informations or experiences about speed control on a
low voltage (28V) AC 2-phase motor (that kind of motor that uses two
windings, and a capacitor in series to one of them).
>
> The Stamp side of my project is not the problem, but it is the drive
technology: phase-control with Triac is one solution, but it is generally
said that with inductive loads it is not very reliable at low speeds. Maybe
not - I'm just starting and I didn't try any circuit - but it is a fact that
DC drives are more popular and well known among the homebrewers! Anyway, I
cannot change the motor.
>
> If anybody experienced something for this kind of motors, I will
appreciate his help.
>
> Alberto.
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
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