Quality AC Variable Speed Controller? - Page 1
Forum section: electronics / projects

author: Generalquark
author_rank: Contributor
timestamp: January 01, 2023, 04:07:52 pm
content: Hi,I was looking for variable AC motor speed controller to vary the speed on an AC motor. AC motor would be running on standard 110/120VAC. Current load should not exceed 5 amps normally (Not sure what startup draw is) I see some cheapies on Amazon like the cdmall and Verispeed, but I was wondering if there was something with much less fire hazard. I was hoping to find something under $40. Any help would be appreciated. Thanks!

author: minifloat
author_rank: Contributor
timestamp: January 01, 2023, 04:22:37 pm
content: Hi there,can you give more info about the AC motor?A pic of the motor data plate also helps.I've seen used brand name VFDs on ebay US beginning with 80$.If you can find out a particular VFD also running with 110V, go for it.needs a 3ph capable motor though...br, mf

author: Generalquark
author_rank: Contributor
timestamp: January 01, 2023, 04:48:48 pm
content: It would be for different versions of a tumbler. Something like thehttps://www.amazon.com/Frankford-Arsenal-Separator-Polishing-Reloading/dp/B00HTN4R6O/ref=sr_1_39?keywords=Thumler%27s+Tumbler&qid=1672588129&sr=8-39orhttps://www.amazon.com/Extreme-Tumblers-Rebel-Reloading-Tumbler/dp/B00IOE5K5Y/ref=sr_1_3?crid=X7V5T0H5DYFL&keywords=Thumler%27s+Tumbler+model+b+high+speed&qid=1672591645&sprefix=thumler%27s+tumbler+model+b+high+spee%2Caps%2C111&sr=8-3&ufe=app_do%3Aamzn1.fos.c3015c4a-46bb-44b9-81a4-dc28e6d374b3orhttps://rocktumbler.com/thumlers/model-b-high-speed.shtml

author: minifloat
author_rank: Contributor
timestamp: January 01, 2023, 07:03:45 pm
content: Problem being, motor specs are oh-so-well hiddenhere...https://www.reddit.com/r/RockTumbling/comments/nwvkcg/failed_chicago_electric_tumbler_motor_upgrade_for/...or...https://i.redd.it/e4mk4xnikh471.jpg...I see motor specs of the "Thumler" tumbler model AR2:Code:P-TECHUSAModel 8163-1693 TTM-1693115V 60Hz0.54A 1550RPMThermally protectedInsulation Class BNotice the low RPM for rock tumbling, small brass partsare more with 3000rpm motor.At least I found this info on the Thumler company web page.I suspect speed control with randomly chosen speed cannot be done so easy with these.There are motors, which number of pole pairs can be switched, making it e.g. 1750rpm or 3500rpm(if that's what you're after).Based on pictures of the Thumler AR2, I calculate the barrel is rotating at...* approx. 60rpm for 3000rpm motor speed* approx. 30rpm for 1500rpm motor speed...because of the pulley ratio and axle-to-barrel-diameter ratio.Means, there can't be much power required for the motor.I've seen the same "canned food" build style for fan motors, they aren't that much power either.60rpm on the barrel makes 1sec revolution.Worst case (AR2 spec: 2lbs material = 0.9kg) lets take 1.5kg stuff, have to be lifted by 25cm height (10") every 0.5sec.P = E/t = m x g x h / t = ca. 15N * 0.25m / 0.5sec = 7.5W mechanical. at the barrel.Add some losses and I'd say, something 20...30W electrical power could be well enough.Makes me think, instead of VFD and stuff, another option is a cheap DC lab power supply and a DC motor.This would let you choose the speed randomlyWhat do you think?br, mf

author: Generalquark
author_rank: Contributor
timestamp: January 01, 2023, 10:04:20 pm
content: Thanks for looking into that so deeply, but I need something off the shelf that would work to slow the higher speed one down. Something I could send to someone with no electrical know how that would make it very easy for them. Any thoughts?

author: minifloat
author_rank: Contributor
timestamp: January 02, 2023, 08:57:26 am
content: Today I learned:- this motor build style (I call "food can") is actually NEMA standardized- the motors for the tumblers are mainly shaded pole motorsMaybe give this one...https://www.amazon.com/KB-Electronics-KBWC-15K-Variable-Control/dp/B015X23BHS/...a try?They even sayQuoteso almost everythingJust put it in an electrical box and it's good.The motors for the tumblers have thermal cutoff just in case.The speed controller being overdimensioned amp-wise by factor 10.br, mf

author: Generalquark
author_rank: Contributor
timestamp: January 02, 2023, 03:52:39 pm
content: I will order the one you suggested. That was one of the ones I was looking at when I started the post. You just taught me quite a bit more about the motors than I knew. Thanks Again for all your help. I will try to remember to come back and let you know how it all worked.