Timeline for Controlling a 240V AC Universal Motor with Microcontroller, Optoisolator & TRIAC
Current License: CC BY-SA 4.0
20 events
| when toggle format | what | by | license | comment | |
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| Jan 14, 2022 at 23:10 | history | edited | JRE | CC BY-SA 4.0 | deleted 420 characters in body |
| Aug 1, 2016 at 10:19 | comment | added | user16324 | @CharlesCowie Thanks! I read that as, shunt might possibly work, but probably inefficiently, while series thanks to one current path, is just much easier to get right. And that makes series the universally adopted strategy. | |
| Jul 31, 2016 at 22:03 | comment | added | user80875 | I believe the R/L would need to be much different because the armature and field would need to be designed to operate at the same voltage but draw much different currents. Also, the back emf controls the armature current. Those two things would cause a phase difference between the armature and field. With a series motor, there is only one current path and thus no possibility of phase difference. | |
| Jul 31, 2016 at 21:28 | comment | added | user16324 | @CharlesCowie "if it were shunt wound, it wouldn't work at all with AC power" what stops it working with AC? Both rotor and field reverse polarity at the same time, just as in the series form. Is it the phase shift as the field winding is almost purely inductive? | |
| Jul 31, 2016 at 21:26 | comment | added | user80875 | Universal motors are very sensitive to load. If you take one out of a machine, and operate it without anything connected to the shaft, it will run very fast. The speed is only limited by the friction of the brushes and bearings plus the air drag on the moving parts. It is possible that heating the air and lubricant reduces the load sufficiently to allow the motor to speed up over time. | |
| Jul 31, 2016 at 20:29 | comment | added | MrMongoloid | Alright, thanks for clearing this out. I can add that I've tried the motor directly on the 240 VAC power supply, and it seems to work just fine. Also the RPM kept increasing over time. | |
| Jul 31, 2016 at 20:15 | history | edited | MrMongoloid | CC BY-SA 3.0 | added 325 characters in body |
| Jul 31, 2016 at 20:14 | comment | added | user80875 | If it has a commutator and brushes, it is a universal motor. I found a little information online that seems to confirm it is a universal motor. I think the motor should work fine with the proposed control scheme. Brian Drummond was only warning about shunt connected motors, since a universal motor is series wound, what he said doesn't apply. If it were shunt wound, it wouldn't work at all with AC power. | |
| Jul 31, 2016 at 20:00 | history | edited | MrMongoloid | CC BY-SA 3.0 | deleted 19 characters in body |
| Jul 31, 2016 at 19:55 | history | edited | MrMongoloid | CC BY-SA 3.0 | deleted 19 characters in body |
| Jul 31, 2016 at 19:44 | comment | added | MrMongoloid | @Charles Cowie, I'm not certain, but I think so. It got brushes ect. It's not an induction motor, but what else could it be? | |
| Jul 31, 2016 at 19:44 | comment | added | MrMongoloid | @Brian Drummond, Very interesting. I need to take a closer look at your suggestion. So you mean it wont work at all, or just behave in at very unpredictable way? | |
| Jul 31, 2016 at 19:07 | comment | added | user80875 | Are you certain the motor is a universal motor? | |
| Jul 31, 2016 at 19:06 | comment | added | user80875 | @Brian Drummond Universal motors are series wound by definition. | |
| Jul 31, 2016 at 18:58 | comment | added | user16324 | Controlling a Universal motor this way won't do quite what you expect. You'll need to separate its field and rotor windings, and keep the field winding connected to the full supply voltage (assuming it's shunt wound). Otherwise the speedup (from field reduction) and slowdown (from rotor voltage reduction) will cancel out. | |
| Jul 31, 2016 at 18:49 | comment | added | Transistor | Pop the motor details into the question (rather than spread through the comments) so that all the relevant info is there. +1 for a very well written first question. | |
| Jul 31, 2016 at 18:48 | answer | added | Transistor | timeline score: 4 | |
| Jul 31, 2016 at 18:25 | history | edited | Transistor | CC BY-SA 3.0 | Embedded image and tidied formatting. |
| Jul 31, 2016 at 18:25 | review | First posts | |||
| Jul 31, 2016 at 18:27 | |||||
| Jul 31, 2016 at 18:20 | history | asked | MrMongoloid | CC BY-SA 3.0 |