Dominicff Report post Posted December 7, 2016 Hi, Has anyone ever tried to use a dimmer switch to slow down and control the speed of a clutch motor ? I have a Pfaff 194 post bed. The pulley is the smallest it can have, the motor is a 1725 rpm and it starts to fast. One tech told me to oil my clutch by removing the cover and putting oil on the flywheel to make it slip and slow it down! Thanks! I kinda screw up one of my bag because of it Quote Share this post Link to post Share on other sites
JLSleather Report post Posted December 7, 2016 I"M the dimmest switch at my sewing machine, but it sounds like you need a speed reducer. Dual pulley, different sizes, trade torque for speed.... Quote Share this post Link to post Share on other sites
TonyRV2 Report post Posted December 7, 2016 14 minutes ago, Dominicff said: Hi, Has anyone ever tried to use a dimmer switch to slow down and control the speed of a clutch motor ? I have a Pfaff 194 post bed. The pulley is the smallest it can have, the motor is a 1725 rpm and it starts to fast. One tech told me to oil my clutch by removing the cover and putting oil on the flywheel to make it slip and slow it down! Thanks! I kinda screw up one of my bag because of it If this has an A.C. motor, which I'm assuming it does, then a dimmer switch will not do the job. Dimmer switches, through an electronic device called a triac, control the average power going to a light bulb for instance. The speed of an A.C. motor cannot be properly controlled using this method as their speed is dependant on the frequency of the A.C voltage. This is why there are devices called variable frequency drives specifically for this purpose. Like I said though, I'm assuming here that its an A.C. motor. However if its a D.C. motor it still won't work with a standard dimmer switch. What could be used though is a variable resistor of suitable electrical specification. D.C. motors can be speed controlled by varying the voltage to the motor, which can be done with a rheostat or potentiometer, both are types of variable resistors. There are many applications where this is done with a foot pedal although modern foot pedals use solid state electronic devices to do the same job for better efficiency. Sorry for being a bit wordy here, but the bottom line is no....you cannot use a dimmer switch. Quote Share this post Link to post Share on other sites
Dwight Report post Posted December 7, 2016 (edited) Yep, . . . what ^^^^^ he said. Having been an electrician for the best part of the last 53 years, . . . I can make a guess that you will burn up the dimmer switch trying to slow that motor. Now you MIGHT GET LUCKY in that the motor is smaller than I imagine, . . . and the switch is larger than I would think, . . . but for all tense and purposes, . . . you are probably looking to find a blown breaker, house full of smoke, and an attitude that will make you wish you did not do that. May God bless, Dwight Edited December 7, 2016 by Dwight Quote Share this post Link to post Share on other sites
Uwe Report post Posted December 7, 2016 (edited) I doubt a regular dimmer switch will work. There are special motor speed controllers for motorized shop tools like routers and portable fans, etc. These *may* work to slow down a clutch motor, but you'll very likely also loose torque. Edited December 7, 2016 by Uwe Quote Share this post Link to post Share on other sites
dikman Report post Posted December 7, 2016 As has been said, won't work, will go poof and smoke a bit. Clutch motors are induction motors and there is no cheap way to slow them down electrically. You have three options - fit a speed reducer pulley, swap it for a servo motor (most economical way to get speed control) or swap the motor for a 3-phase motor and use a VFD to control it. The device Uwe lists is meant for electric power tools that use brush motors, will also go poof if connected to an induction motor. Quote Share this post Link to post Share on other sites
Dominicff Report post Posted December 7, 2016 4 hours ago, Dwight said: Yep, . . . what ^^^^^ he said. Having been an electrician for the best part of the last 53 years, . . . I can make a guess that you will burn up the dimmer switch trying to slow that motor. Now you MIGHT GET LUCKY in that the motor is smaller than I imagine, . . . and the switch is larger than I would think, . . . but for all tense and purposes, . . . you are probably looking to find a blown breaker, house full of smoke, and an attitude that will make you wish you did not do that. May God bless, Dwight Lol thank you !! Quote Share this post Link to post Share on other sites
