Question regarding ECM motors.

[few2many]

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.

[BBeerme]

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)?

[few2many]

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.

[Core_d]

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.


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[few2many]

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.

[SKY-DDC]

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.


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[BBeerme]

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.

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.


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[ga-hvac-tech]

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.


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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...

[few2many]

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.

[ga-hvac-tech]

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...

[few2many]

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.

[ga-hvac-tech]

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.

[few2many]

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.

[Swf]

Ecm motors can change speed on the fly, the motor is control digitally and voltage is rectified to the motor windings based on speed / torque demand