Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Single phase 220VAC motor speed control

Status
Not open for further replies.

twinsen

Full Member level 1
Joined
Dec 27, 2001
Messages
96
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,288
Activity points
837
Hi all

I want to speed control my lathe at home. I am not a wizz in power electronics. Other than gating a SCR or something like that is there a more intelligent way to control the speed of an AC motor, or would it be better to rather look for a DC replacement?
 

If you don't need large power,I think Dc motor is better,Dc motor is safty.
and you can easy to control dc motor with speed adjust.
 

AC motor control is alittle coplicated but can be discussed in 3 steps:
1.rectify and filter input AC voltage by a bridge and a capacitor.
2.use a full bridge cunstracted with IGBTs and use opto-coupler/driver or bootstrap driver for driving top switches (they require floating ground)
3.controll the speed by PWM generator driving the full bridge

refer to applicatin notes available @ www.irf.com for more infos!
BEST!
 

If you have a 1-phase AC motor and use feedback from the axle it can be simple if it’s the right kind of motor. If it is a 3-phase motor it’s a lot more complicated. What kind of power (Watts) are we talking about?

Ante :roll:
 

I have tried commercial drives for synchronous single-phase motors, i.e., not AC/DC universal motors. You will lose torque and the range of useful control will probably be too small. As a result, I switched to DC motors with AC-powered drives and three-phase motors with variable frequency drives (VFD). 3-phase VFD's running from single-phase are not very expensive and make 3-phase quite practical for home use.

It happens that I used DC for my lathe and VFD for a drill press, molder/shaper, and scroll saw. Both methods give a range of control from a walk to full speed with good torques across the full range. The main difference that I have seen is that VFD's take awhile to get going (like a second or two). DC is almost instantaneous. So, if I were to recommend anything it would be to use DC on the lathe because I know that works well. That is not to say in the least that a VFD with 3-phase wouldn't work as well. I just haven't tried it.

I have used KB Drives (KB Electronics AC Motor, DC Motor Drives & Fan Speed Controls), Hitachi, and another brand that was on sale. **broken link removed**, if you are in the US, has good prices on those brands. The DC drive for my lathe is KB and was only about $125 USD new.

John

Edit: I forget to add that DC motors also provide easy braking. The lathe mentioned above is a Prazi SD300 and does not have half-nuts for threading. The instant stop comes in very convenient when threading on that machine.
 
Last edited:

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top