Connect with us

help with variable speed motor

Discussion in 'General Electronics Discussion' started by leeknivek, Jul 18, 2019.

  1. leeknivek

    leeknivek

    4
    0
    Jul 18, 2019
    Hello -

    i have a few motors that i got from a job, trying to figure out how they go. they are 1/2hp 120vac single phase, and controlled with 24vdc, i think. i was unable to find a manufacturer or schematic or anything. these came out of some blower fans built into ceiling grills. i do hvac for a living, so bear with me please :)

    there are three 14 gauge wires (black, white, green) & four 22 gauge wires (red, black, white, green).

    the motor works, however i can't figure out how to control it. with everything connected, the motor revs up to 200 rpm for a few seconds, then 1200rpm for a few seconds, brakes, then repeats. putting a heavier load on the motor causes it to stay at 1200rpm.

    there is one potentiometer, on the board says "rpm control", doesn't seem to change anything much - at one point it changed the delay on it's 200-1200-brake cycle.

    there are two banks of DIP switches, one with two switches, one with eight switches. #1 on the 8-switch DIP says "on", 1 & 2 on 8-switch DIP turns everything off. the rest don't seem to do anything.

    there are test leads built into the board, as well as two phone jacks. haven't played with those yet.

    there are two more 2-pin connectors on the board, one goes to two 24g wires, red and black, perhaps a thermostat or some other external control. tried shorting them, connecting to a pot, no change. maybe needs a hot signal. the second two-pin connector says "ext rpm control", i think that calls for 10vdc, don't have a supply for that handy.

    they are essentially set up as i took them apart. i don't know how much of that^ is relevant but thought i'd tell all i know about them.

    i can solder ok and would like to just bypass this whole board, not sure where to start. i don't have them in front of me but i can take some photos tomorrow.
     
  2. Bluejets

    Bluejets

    3,444
    698
    Oct 5, 2014
    Without knowing brand, style, specs of the unit, your guess is as good as anyone elses. Contary to popular belief, McGyver's colour codes and which wire to cut are all simply fantacy.
    If you can show some detail, nameplate or whatever it may help. Usually make and model required though.
     
    Martaine2005 likes this.
  3. leeknivek

    leeknivek

    4
    0
    Jul 18, 2019
    [​IMG]

    having a hard time uploading photos from my phone -

    that nameplate is on the motor, there is a second nameplate on the bottom part of the motor where the control wires go.

    US MOTORS PerfectSpeed

    EEPROM DATA E077906820000
    PART NUMBER X177906810001

    IN 120/208-240 VAC 1 PH 6.6/4.0-4.8 & 6.2/4.2-3.8 AMPS

    US PATS xxx xxx xxx FOR USE WITH AA251702
    xxx xxx xxx xxx xxx FOR USE WITH 1/2HP MOTOR
    xxx xxx xxx xxx xxx MO55PWCVU-0345

    NIDEC MOTOR CORPORATION www.usmotors.com
     
    Last edited: Jul 18, 2019
  4. Martaine2005

    Martaine2005

    2,376
    627
    May 12, 2015
     
  5. Martaine2005

    Martaine2005

    2,376
    627
    May 12, 2015
    Why do we have 'Spoiler'?.
    This isn't a quiz.....

    Martin
     
  6. leeknivek

    leeknivek

    4
    0
    Jul 18, 2019
    click the spoiler to reveal the photo. helps to not clog up the thread - sorry

    i zoomed in on a photo of the pcb and found that the four control wires are labeled,

    PWM - red
    COM - green
    TACH - black
    ENBL - white

    [​IMG]
     
    Last edited: Jul 18, 2019
  7. Braeden Hamson

    Braeden Hamson

    207
    13
    Feb 18, 2016
    Not sure if you're still around, but it looks like you can adjust the speed be feeding 0-10v into those screw terminals. Apparently it can also take serial communications and PWM.
     
  8. leeknivek

    leeknivek

    4
    0
    Jul 18, 2019
    thanks, i was curious of that. i did find that it has three "modes" - constant rpm, constant torque, and constant cfm (being a blower fan, fed from a probe). i am not sure what mode it is in or how to change it.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-