I have an old HVAC blower motor which was removed from
a Carrier air handler on grounds it was defective. It's
half horsepower, with ECM 3.0 controls. It has an AC
input for motor power and a four pin control connector
marked common, Rx, Tx and V+. Physically it's in perfect
shape.
On the bench it seems to work fine. The test procedure
applies 24 VAC between common and Rx, the motor soft
starts and runs smoothly.
I'd like to adapt the motor to other uses and if possible
exploit the variable speed feature, but there's no info
readily available that describes the control signals.
There's a YouTube video at
https://www.youtube.com/watch?v=Zaj_a68lry8
showing a physical teardown implying a digital
interface is used, but no electrical testing is
shown.
Does anybody have further information that might be
used to communicate with the controller?
Thanks for reading,--
bob prohaska
In article <umk6jh$eaiu$1@dont-email.me>,
bob prohaska <bp@www.zefox.net> wrote:
I have an old HVAC blower motor which was removed from
a Carrier air handler on grounds it was defective. It's
half horsepower, with ECM 3.0 controls. It has an AC
input for motor power and a four pin control connector
marked common, Rx, Tx and V+. Physically it's in perfect
shape.
On the bench it seems to work fine. The test procedure
applies 24 VAC between common and Rx, the motor soft
starts and runs smoothly.
I'd like to adapt the motor to other uses and if possible
exploit the variable speed feature, but there's no info
readily available that describes the control signals.
There's a YouTube video at
https://www.youtube.com/watch?v=Zaj_a68lry8
showing a physical teardown implying a digital
interface is used, but no electrical testing is
shown.
Does anybody have further information that might be
used to communicate with the controller?
If you have access to a working version of that motor
attach a scope to Rx and Tx. At least I managed to
find out how to control a blower to mix gas and air
with my central heating.
albert <albert@cherry.(none)> wrote:
In article <umk6jh$eaiu$1@dont-email.me>,
bob prohaska <bp@www.zefox.net> wrote:
I have an old HVAC blower motor which was removed from
a Carrier air handler on grounds it was defective. It's
half horsepower, with ECM 3.0 controls. It has an AC
input for motor power and a four pin control connector
marked common, Rx, Tx and V+. Physically it's in perfect
shape.
On the bench it seems to work fine. The test procedure
applies 24 VAC between common and Rx, the motor soft
starts and runs smoothly.
I'd like to adapt the motor to other uses and if possible
exploit the variable speed feature, but there's no info
readily available that describes the control signals.
There's a YouTube video at
https://www.youtube.com/watch?v=Zaj_a68lry8
showing a physical teardown implying a digital
interface is used, but no electrical testing is
shown.
Does anybody have further information that might be
used to communicate with the controller?
If you have access to a working version of that motor
attach a scope to Rx and Tx. At least I managed to
find out how to control a blower to mix gas and air
with my central heating.
The test I used consisted of merely applying 24 volts AC
between Rx and Common. How that can work via a digital
input eludes me.
I don't have a scope. Can you describe what you did
to control your motor? I gather certain "smart" motors
have dual-use inputs. While I have the running motor
I do not have access to the equipment it came from so
It's impossible to see what signals were in use.
Thanks for writing!
bob prohaska
In article <umsdn0$1qlm1$1@dont-email.me>,
bob prohaska <bp@www.zefox.net> wrote:
albert <albert@cherry.(none)> wrote:
In article <umk6jh$eaiu$1@dont-email.me>,
bob prohaska <bp@www.zefox.net> wrote:
I have an old HVAC blower motor which was removed from
a Carrier air handler on grounds it was defective. It's
half horsepower, with ECM 3.0 controls. It has an AC
input for motor power and a four pin control connector
marked common, Rx, Tx and V+. Physically it's in perfect
shape.
On the bench it seems to work fine. The test procedure
applies 24 VAC between common and Rx, the motor soft
starts and runs smoothly.
I'd like to adapt the motor to other uses and if possible
exploit the variable speed feature, but there's no info
readily available that describes the control signals.
There's a YouTube video at
https://www.youtube.com/watch?v=Zaj_a68lry8
showing a physical teardown implying a digital
interface is used, but no electrical testing is
shown.
Does anybody have further information that might be
used to communicate with the controller?
If you have access to a working version of that motor
attach a scope to Rx and Tx. At least I managed to
find out how to control a blower to mix gas and air
with my central heating.
The test I used consisted of merely applying 24 volts AC
between Rx and Common. How that can work via a digital
input eludes me.
I don't have a scope. Can you describe what you did
to control your motor? I gather certain "smart" motors
have dual-use inputs. While I have the running motor
I do not have access to the equipment it came from so
It's impossible to see what signals were in use.
The blower was working in the central heating system.
The power pins were just 0 and 24 V, permanently.
It took some effort to attach a thin wire to the control pin.
Then is become obvious that it was a pwm signal of 2 Khz,
with the width controlling the speed of the blower.
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