Results 1 to 13 of 13
  1. #1
    Join Date
    Jan 2010
    Location
    Arizona
    Posts
    124
    Post Likes

    Question regarding ECM motors.

    Can a 3 speed ecm blower switch between speeds on the fly/ while running? Or does it need to come to a complete stop first?
    Working on a Trane/American Standard Tem4 air handler. The ecm blower has 3 speed taps, separated by by just over 100 cfm each. It's factory set on 2, providing somewhat weak but acceptable air flow, and good dehumidification. High speed seems better for the system overall. I'd like to place a time delay that runs medium for a time to dehumidify, then high for the remainder of the cycle.
    Back to the question, can an ECM motor be switched from mid to high while running? I'm just not sure if the controller can safely handle switching from mid to high while running.
    I tried calling Trane, who said they don't provide tech support and to call the dealer. Called the Trane distributor where it was purchased, they didn't know.

  2. #2
    Join Date
    May 2014
    Location
    Bay Area California
    Posts
    26,612
    Post Likes
    My guess is yes, but it is only a guess.

    Think about it. What happens when it switches from heat to cooling? Or from the fan on position (lower speed) to cooling (higher speed)?
    I do a triple evac with nitro to remove non condensables.

  3. #3
    Join Date
    Jan 2010
    Location
    Arizona
    Posts
    124
    Post Likes
    Thread Starter
    Good points. I know that it typically starts up from a stop with just one me sognal. But if the blower is "on", and there's a call for cooling or heating, it's different because it's already running. T stat Control to the same speed tap.
    Heat mode starts with two signals. The speed tap, and the signal for heat which is faster.
    I'm asking if the speed can change from tap 2, to tap 3, while running in cool mode.
    I'd just give it a try, but it would be expensive if it fails.

  4. #4
    Join Date
    Dec 2012
    Location
    columbus, OH
    Posts
    7,044
    Post Likes
    What ecm is 3 speed? Sure its not 5, an x13.

    I dont believe it would cause an issue. Also most are programmed to use the highest speed selected if you energize multiple speed taps at once.


    Sent from my iPhone using Tapatalk

  5. #5
    Join Date
    Jan 2010
    Location
    Arizona
    Posts
    124
    Post Likes
    Thread Starter
    Quote Originally Posted by Core_d View Post
    What ecm is 3 speed? Sure its not 5, an x13.

    I dont believe it would cause an issue. Also most are programmed to use the highest speed selected if you energize multiple speed taps at once.
    I'm not as familiar with ECM motors. All I know is what's in the manual and what I've read elsewhere. The Trane TEM4 manual says 3 different speeds. Wiring diag shows 5 taps. It shows tap 1 and 2 connected. Then t stat G goes to tap 3, or 4, or 5 for speed change.

  6. #6
    Join Date
    May 2014
    Posts
    14
    Post Likes
    Quote Originally Posted by few2many View Post
    Can a 3 speed ecm blower switch between speeds on the fly/ while running? Or does it need to come to a complete stop first?
    Working on a Trane/American Standard Tem4 air handler. The ecm blower has 3 speed taps, separated by by just over 100 cfm each. It's factory set on 2, providing somewhat weak but acceptable air flow, and good dehumidification. High speed seems better for the system overall. I'd like to place a time delay that runs medium for a time to dehumidify, then high for the remainder of the cycle.
    Back to the question, can an ECM motor be switched from mid to high while running? I'm just not sure if the controller can safely handle switching from mid to high while running.
    I tried calling Trane, who said they don't provide tech support and to call the dealer. Called the Trane distributor where it was purchased, they didn't know.
    The ECM (Electronically Controlled Motor) motors I have worked with use a 2-10 volt DC input to control speed. They are like a poor mans VFD (Variable Frequency Drive). Below 2 volts to stop, 2-10 volts spans 0-100% speeds. You can ramp them up and down all day since it’s electronic controlled. But you need a controller that can output 0-10 volts. That’s usually the difficult part using inexpensive thermostats. The electric companies are giving substantial credits for using ECM motors so we should see more compatibility in the future.


    Sent from my iPhone using Tapatalk

  7. #7
    Join Date
    May 2014
    Location
    Bay Area California
    Posts
    26,612
    Post Likes
    I think if it the five pin input for control, then it's 24 VAC.

    If it is the 16 pin plug, then it could be most anything.


    Quote Originally Posted by SKY-DDC View Post
    The ECM (Electronically Controlled Motor) motors I have worked with use a 2-10 volt DC input to control speed. They are like a poor mans VFD (Variable Frequency Drive). Below 2 volts to stop, 2-10 volts spans 0-100% speeds. You can ramp them up and down all day since it’s electronic controlled. But you need a controller that can output 0-10 volts. That’s usually the difficult part using inexpensive thermostats. The electric companies are giving substantial credits for using ECM motors so we should see more compatibility in the future.


    Sent from my iPhone using Tapatalk
    I do a triple evac with nitro to remove non condensables.

  8. #8
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    44,306
    Post Likes
    Quote Originally Posted by SKY-DDC View Post
    The ECM (Electronically Controlled Motor) motors I have worked with use a 2-10 volt DC input to control speed. They are like a poor mans VFD (Variable Frequency Drive). Below 2 volts to stop, 2-10 volts spans 0-100% speeds. You can ramp them up and down all day since it’s electronic controlled. But you need a controller that can output 0-10 volts. That’s usually the difficult part using inexpensive thermostats. The electric companies are giving substantial credits for using ECM motors so we should see more compatibility in the future.


    Sent from my iPhone using Tapatalk
    Quote Originally Posted by BBeerme View Post
    I think if it the five pin input for control, then it's 24 VAC.

    If it is the 16 pin plug, then it could be most anything.
    In residential heating and AC equipment, we find TWO (2) different designs of ECM motors...
    One is called 'constant torque' (also called X13)... the other is called variable speed (VS).

    The first (constant torque/X13) has 4 or 5 speed taps and runs at specific speeds...
    The latter (VS) has the ability to run at different speeds automatically.
    And yes, they are really nothing more than VFD driven 3 ph motors.

    As BB said... does it have 5x speed taps???

    Ask to have this moved to PRO forum... we are not really supposed to discuss tech stuff in open forums...
    GA-HVAC-Tech

    Your comfort, Your way, Everyday!

    GA's basic rules of home heating and AC upgrades:
    *Installation is more important than the brand of equipment
    *The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
    *Cheap is not good, good is not cheap; however expensive is not a guarantee of quality!
    Choose your contractor wisely!

  9. #9
    Join Date
    Jan 2010
    Location
    Arizona
    Posts
    124
    Post Likes
    Thread Starter
    Quote Originally Posted by ga-hvac-tech View Post
    Ask to have this moved to PRO forum... we are not really supposed to discuss tech stuff in open forums...
    This is the motor/control section.
    This is a motor/control question.
    I've described the motor as having 5 taps, 3 speeds, per manual.

  10. #10
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    44,306
    Post Likes
    Quote Originally Posted by few2many View Post
    This is the motor/control section.
    This is a motor/control question.
    I've described the motor as having 5 taps, 3 speeds, per manual.
    Yes...

    However I found the post on HVAC-Talk... and us posters are asked to not get too technical on 'open' forums (HVAC-Talk has a 'no DIY' policy... mostly to protect HO's from hurting themselves).

    Was just suggesting how to get into a private environment (PRO section not open section)... where we can go into detail on the question you asked.

    Note that I looked... the electrical forums that are shown on HVAC-Talk have both open and PRO sections...
    All one has to do, is click on the small black triangle at the bottom-left of a post, and ask the MODS to move the thread to a PRO forum. ALL the folks who are PRO members will still have access... yet HO's and DIY folks will not be able to see it.

    Nothing negative meant... just following the rules us HVAC/R PRO's have been under for years and years here...
    GA-HVAC-Tech

    Your comfort, Your way, Everyday!

    GA's basic rules of home heating and AC upgrades:
    *Installation is more important than the brand of equipment
    *The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
    *Cheap is not good, good is not cheap; however expensive is not a guarantee of quality!
    Choose your contractor wisely!

  11. #11
    Join Date
    Jan 2010
    Location
    Arizona
    Posts
    124
    Post Likes
    Thread Starter
    Yeah it's cool. I haven't been too active here, but I do recall when most of these rules and pro/public forums came about.
    I found a thread about a week older than mine, asking basically the same question, in the AOP forum. Unfortunately I can't reply to ask of the guy found a resolution or final answer.

  12. Likes ga-hvac-tech liked this post.
  13. #12
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    44,306
    Post Likes
    Quote Originally Posted by few2many View Post
    Yeah it's cool. I haven't been too active here, but I do recall when most of these rules and pro/public forums came about.
    I found a thread about a week older than mine, asking basically the same question, in the AOP forum. Unfortunately I can't reply to ask of the guy found a resolution or final answer.
    As I understand things...

    Forum ownership is kinda like owning auto dealerships... holding companies hold lots and lots of them...
    And tell the forum management what the rules will be.

    Sadly... H-talk is owned by a holding co... so we have to follow their rules.

    If you want a more detailed understanding... click on my profile and send me an Email... please reference this discussion...
    Will be glad to carry on a private conversation.
    GA-HVAC-Tech

    Your comfort, Your way, Everyday!

    GA's basic rules of home heating and AC upgrades:
    *Installation is more important than the brand of equipment
    *The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
    *Cheap is not good, good is not cheap; however expensive is not a guarantee of quality!
    Choose your contractor wisely!

  14. #13
    Join Date
    Jan 2010
    Location
    Arizona
    Posts
    124
    Post Likes
    Thread Starter
    No problem following rules. Didn't really think I was outside them, maybe skirting them a bit!.
    If you want a clearer understanding of the motor I'm working with, you can find the TEM4 manuals easily. I Can't post pics or files.
    Thanks.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Contracting Business
HPAC Engineering
EC&M
CONTRACTOR