I'm the recipient of an EC motor from an HVAC system
that was removed as "defective". I know it runs, since
supplying 120 VAC to the power terminals and 24V AC to
the control terminal makes it run, unfortunately in the
wrong direction to drive my South Bend Light Ten lathe.
The control connections are completely obscure, apart
from the one pin that runs the motor when it sees 24V..
There are lots of packaged VFDs on Amazon, some for less
than $100, that accept single phase 120v input and are
said to drive "most" 3 phase motors within their size
range, typically 1-3 kW. This motor is a Genteq ECM 3.0,
I see only the three power wires going from control to
motor, no tach or feedback connections. It's rated at
half horsepower, with no electrical specs on the tag.
Turned by hand, it does not seem to cog, so I don't
think it's a PM motor.
Does anybody have experince or ideas about this notion?
Thanks for reading, and any ideas!
bob prohaska
I'm the recipient of an EC motor from an HVAC system
that was removed as "defective". I know it runs, since
supplying 120 VAC to the power terminals and 24V AC to
the control terminal makes it run, unfortunately in the
wrong direction to drive my South Bend Light Ten lathe.
The control connections are completely obscure, apart
from the one pin that runs the motor when it sees 24V..
There are lots of packaged VFDs on Amazon, some for less
than $100, that accept single phase 120v input and are
said to drive "most" 3 phase motors within their size
range, typically 1-3 kW. This motor is a Genteq ECM 3.0,
I see only the three power wires going from control to
motor, no tach or feedback connections. It's rated at
half horsepower, with no electrical specs on the tag.
Turned by hand, it does not seem to cog, so I don't
think it's a PM motor.
Does anybody have experince or ideas about this notion?
Thanks for reading, and any ideas!
bob prohaska
------------------------
The general info I found on EC motors suggest they may be internally reversible. Does it have an identifying nameplate you could look up?
The general info I found on EC motors suggest they may be internally reversible. Does it have an identifying nameplate you could look up?
BP wrote in message news:10unifk$u6tu$1@dont-email.me...
Jim Wilkins <muratlanne@gmail.com> wrote:>
The general info I found on EC motors suggest they may be internally
reversible. Does it have an identifying nameplate you could look up?
I think that's true, but the "identifying nameplate" isn's much help.
It specifies "ECM 3.0" and nothing else. I believe that implies a
digital interface of some sort but I've had no luck learning more.
I was able to glean the go/no-go test using 24VAC and that's it.
A generic 3 phase VFD looks superficially like the simplest approach.
Thanks for writing,
bob prohaska
-------------------------------
If it rectifies the incoming AC to DC for an inverter the line frequency will have little or no effect, though reduced voltage might.
I'm the recipient of an EC motor from an HVAC system
that was removed as "defective". I know it runs, since
supplying 120 VAC to the power terminals and 24V AC to
the control terminal makes it run, unfortunately in the
wrong direction to drive my South Bend Light Ten lathe.
The control connections are completely obscure, apart
from the one pin that runs the motor when it sees 24V..
There are lots of packaged VFDs on Amazon, some for less
than $100, that accept single phase 120v input and are
said to drive "most" 3 phase motors within their size
range, typically 1-3 kW. This motor is a Genteq ECM 3.0,
I see only the three power wires going from control to
motor, no tach or feedback connections. It's rated at
half horsepower, with no electrical specs on the tag.
Turned by hand, it does not seem to cog, so I don't
think it's a PM motor.
Does anybody have experince or ideas about this notion?
Thanks for reading, and any ideas!
bob prohaska
BP wrote in message news:10unifk$u6tu$1@dont-email.me...
Jim Wilkins <muratlanne@gmail.com> wrote:>
The general info I found on EC motors suggest they may be internally
reversible. Does it have an identifying nameplate you could look up?
I think that's true, but the "identifying nameplate" isn's much help.
It specifies "ECM 3.0" and nothing else. I believe that implies a
digital interface of some sort but I've had no luck learning more.
I was able to glean the go/no-go test using 24VAC and that's it.
A generic 3 phase VFD looks superficially like the simplest approach.
Thanks for writing,
bob prohaska
-------------------------------
If it rectifies the incoming AC to DC for an inverter the line frequency will have little or no effect, though reduced voltage might.
After reading Jim's description a VFD would be of no use to you at all.
I might try a variable power supply on the input.-a 0-10 and 0-5 vdc are common input signal voltages for motor controllers.-a I don't see any
reason why it couldn't be 0-24.-a On the motor controllers I am most familiar with the signal voltage is usually DC, but AC is much easier to derive from an AC source like wall power.
After reading Jim's description a VFD would be of no use to you at all. I might try a variable power supply on the input. 0-10 and 0-5 vdc are
common input signal voltages for motor controllers. I don't see any
reason why it couldn't be 0-24. On the motor controllers I am most
familiar with the signal voltage is usually DC, but AC is much easier to derive from an AC source like wall power.
On 5/21/2026 2:41 PM, Jim Wilkins wrote:
BP wrote in message news:10unifk$u6tu$1@dont-email.me...
Jim Wilkins <muratlanne@gmail.com> wrote:>
The general info I found on EC motors suggest they may be internally
reversible. Does it have an identifying nameplate you could look up?
I think that's true, but the "identifying nameplate" isn's much help.
It specifies "ECM 3.0" and nothing else. I believe that implies a
digital interface of some sort but I've had no luck learning more.
I was able to glean the go/no-go test using 24VAC and that's it.
A generic 3 phase VFD looks superficially like the simplest approach.
Thanks for writing,
bob prohaska
-------------------------------
If it rectifies the incoming AC to DC for an inverter the line
frequency will have little or no effect, though reduced voltage might.
After reading Jim's description a VFD would be of no use to you at all.
I might try a variable power supply on the input.-a 0-10 and 0-5 vdc are common input signal voltages for motor controllers.-a I don't see any
reason why it couldn't be 0-24.-a On the motor controllers I am most familiar with the signal voltage is usually DC, but AC is much easier to derive from an AC source like wall power.
I wonder if its signal voltage for control, and pulse width modulation
for speed.-a Pulse width modulation has been in commercial use for retail products for 50 years that I am aware of.-a At anything under 100% on its supposed to be a huge power saver over other methods of speed
controlling a motor.-a Minn Kota sold it as an add on for 12V electric trolling motors 50ish years ago.-a I used a pulse width modulation
control on a universal motor on a lathe maybe 10 years ago.
I'm not up much on brushless DC motors.-a Universal DC motors don't have much power/torque at low RPM, but the pulse width modulation control was much better than a voltage level control.
Perhaps I posed my question in the wrong way. The ECM motor
is basically a 3-phase motor with its own VFD, which I can't
figure out how to test extensively or use.
The idea was to discard the ECM 3.0 assembly entirely and replace
it with a standalone cheap VFD. The ECM 3.0 unit was declared "bad"
by the service tech; the fact that the motor runs in test mode
suggests the motor, at least, is OK. If the controller is inscrutable
just toss it and buy a cheap VFD.
Is it sufficient to find a VFD with the right power and voltage
ratio, or do I have to match more detailed specification? All
I know about the motor is that it uses 120 volts, is rated at
half a horsepower and runs at around 1000-2000 rpm.
That's the experiment I was asking about, not how to re-use the
entire unit intact.
Thanks for reading, and all the replies!
bob prohaska
BP wrote in message news:10v00fc$ss18$1@dont-email.me...
Perhaps I posed my question in the wrong way. The ECM motor
is basically a 3-phase motor with its own VFD, which I can't
figure out how to test extensively or use.
The idea was to discard the ECM 3.0 assembly entirely and replace
it with a standalone cheap VFD. The ECM 3.0 unit was declared "bad"
by the service tech; the fact that the motor runs in test mode
suggests the motor, at least, is OK. If the controller is inscrutable
just toss it and buy a cheap VFD.
Is it sufficient to find a VFD with the right power and voltage
ratio, or do I have to match more detailed specification? All
I know about the motor is that it uses 120 volts, is rated at
half a horsepower and runs at around 1000-2000 rpm.
That's the experiment I was asking about, not how to re-use the
entire unit intact.
Thanks for reading, and all the replies!
bob prohaska
-----------------------------------
My only experiment with a regular 3 phase motor
run capacitor in series with the third phase. A Variac with an ammeter showed that the current wasn't excessive as I raised the voltage until
it turned. 12uF turned it but not as well. They are the only run caps I have.
Before powering the motor I tested from the windings to the frame with a Megger to see if it had been rejected for excessive leakage. I've bought
a few used items that failed that test until cleaned.
Perhaps I posed my question in the wrong way. The ECM motor
is basically a 3-phase motor with its own VFD, which I can't
figure out how to test extensively or use.
The idea was to discard the ECM 3.0 assembly entirely and replace
it with a standalone cheap VFD. The ECM 3.0 unit was declared "bad"
by the service tech; the fact that the motor runs in test mode
suggests the motor, at least, is OK. If the controller is inscrutable
just toss it and buy a cheap VFD.
Is it sufficient to find a VFD with the right power and voltage
ratio, or do I have to match more detailed specification? All
I know about the motor is that it uses 120 volts, is rated at
half a horsepower and runs at around 1000-2000 rpm.
That's the experiment I was asking about, not how to re-use the
entire unit intact.
Thanks for reading, and all the replies!
bob prohaska
... While the input to the packaged controller seems to be 110VAC the
output to the motor windings can be anything DC. ...
"Bob La Londe"-a wrote in message news:10v2bo9$1l4n1$2@dont-email.me...
... While the input to the packaged controller seems to be 110VAC the
output to the motor windings can be anything DC.-a ...
While the name suggests that the motor runs on DC, actually the motor windings get AC created in a DC to AC power controller by magic
crystals. DC has no phase.
https://www.jkongmotor.com/comprehensive-introduction-to-3-phase-bldc- motors.html
"A BLDC motor cannot operate directly from a DC supply. It requires an Electronic Speed Controller (ESC), which converts the DC input into a three-phase AC output that powers the motor. The ESC determines how fast
the motor spins by adjusting the frequency and duration of current
pulses sent to the stator windings."
Traditional DC-powered motors had brushes and a commutator to switch the current progressively around the rotor as it turns, keeping its magnetic field ahead of and pulling against the static magnetic field in the DC- powered outer windings.
3 phase motors power the stationary outer windings sequentially to
create a rotating magnetic field that drags the rotor around, without brushes to spark and wear out. Nicola Tesla daydreamed the idea while
idling on a park bench.
... Well I feel like an idiot.
"Bob La Londe"-a wrote in message news:10v51v3$2bsil$1@dont-email.me...
... Well I feel like an idiot.
You needn't, it isn't common knowledge.
I didn't know that until I worked with custom designed implementations
of such motors and their controls at Segway; they drive the wheels. The explanation of how they work was similar to what I had learned about computer synthesized digital radio for NASA.
"Bob La Londe" wrote in message news:10v51v3$2bsil$1@dont-email.me...
... Well I feel like an idiot.
You needn't, it isn't common knowledge.
I didn't know that until I worked with custom designed implementations of such motors and their controls at Segway; they drive the wheels. The explanation of how they work was similar to what I had learned about computer synthesized digital radio for NASA.
On 5/26/2026 2:57 PM, Jim Wilkins wrote:
"Bob La Londe"-a wrote in message news:10v51v3$2bsil$1@dont-email.me...
... Well I feel like an idiot.
You needn't, it isn't common knowledge.
I didn't know that until I worked with custom designed
implementations of such motors and their controls at Segway; they
drive the wheels. The explanation of how they work was similar to
what I had learned about computer synthesized digital radio for NASA.
I was going to try to defend my wrongness with, "There are controllers
for sale labeled as 3 phase DC controllers," but wrong is still wrong.
I've bought one of those and used it to convert a car alternator into a motor, not quite brushless as the armature needs DC power to generate a magnetic field. It works quite well.
I've bought one of those and used it to convert a car alternator into a motor, not quite brushless as the armature needs DC power to generate a magnetic field. It works quite well.
"David Billington"-a wrote in message
news:10v5eg6$2enlj$1@dont-email.me...
I've bought one of those and used it to convert a car alternator into a motor, not quite brushless as the armature needs DC power to generate a magnetic field. It works quite well.
-------------------------
How much current did the armature (rotor) take?
I ask because I did a quote for a production line machine that would
measure full alternator outputs to sort them into current rating bins.
All were made the same, the difference was in the size and uniformity
of the magnetic gaps between the fairly rough edged iron core stampings.
I also built and set up a machine that tested voltage clamping when
the battery connection opened during full charge, from corroded
connections on a rough road, called a Load Dump. The energy stored in
the armature dissipates as a voltage spike when the battery can't
accept the full current. [The car company] couldn't test for the
thermal load of rapidly repeating load dumps with their lab equipment,
and their estimate of an adequately sized Zener was too low, it failed
as I watched. That may have been a reason for side terminal batteries. https://en.wikipedia.org/wiki/Load_dump
Before emissions requirements the only electronic device in a car was
the radio which they bought. The electrical engineers the car
companies quickly hired lacked experience with the hot, cold and wet conditions I had seen provided for in Army electronics. One Ph.D.
expected 8 digit voltage accuracy from an op amp circuit, he didn't
know about resistor and capacitor tolerance.
For some reason, perhaps union work rules, only Ford built their own production test equipment, the others had to order it from outside.
The company I worked for was small and lean enough to accept
'oh-by-the-way' modifications and still deliver fast enough to win
many of the bids. Mainly there was no delay from management overhead; meetings and waiting for multiple signatures on a purchase order. Once project manager I could build or buy what I wanted immediately. That's
where I learned both mechanical and electrical fabrication, the full
design and construction of a product.
"David Billington" wrote in message news:10v5eg6$2enlj$1@dont-email.me...
I've bought one of those and used it to convert a car alternator into a motor, not quite brushless as the armature needs DC power to generate a magnetic field. It works quite well.
-------------------------
How much current did the armature (rotor) take?
"David Billington"-a wrote in message news:10vf1v2$uid1$1@dont-email.me...
On 27/05/2026 13:51, Jim Wilkins wrote:
"David Billington"-a wrote in message
news:10v5eg6$2enlj$1@dont-email.me...
I've bought one of those and used it to convert a car alternator into a
motor, not quite brushless as the armature needs DC power to generate a
magnetic field. It works quite well.
-------------------------
How much current did the armature (rotor) take?
I just ran it up and the armature was taking 4A @ 12V. I had heard of
the conversion having run across mention of it on the net and used a
cheap brushless controller bought online and did the necessary to the alternator to connect it up and it works but I haven't a use for it, I
just tried it as a bit of fun.
--------------------------------
Some have used spare alternators and small engines to make high
current battery chargers. Theoretically 1 HP gives 746 Watts.
My high current DC charger is a 50A welding transformer controlled
with a Variac. Being able to adjust the output voltage from zero to
50VDC is useful, low voltage for testing circuit breakers, 14V for car batteries and higher for UPS and golf cart batteries and this very
nice power supply voltage and current regulator: https://lygte-info.dk/review/Power%20DPS5020-USB%20UK.html
With it I found that some inexpensive surface mount thermal breakers
for car audio are little better than fuses, they trip properly the
first time but the contacts burn, heat from current and decrease the subsequent trip points.
By itself the welder supply can charge a 24V battery pair at 30A, but
since the transformer was for stick welding the voltage rises too far
when the batteries near full charge and take less current. The DPS5020
is the better answer, checking voltage and reducing output the cheap one.
| Sysop: | Amessyroom |
|---|---|
| Location: | Fayetteville, NC |
| Users: | 69 |
| Nodes: | 6 (0 / 6) |
| Uptime: | 28:13:16 |
| Calls: | 899 |
| Files: | 1,320 |
| D/L today: |
3 files (12,347K bytes) |
| Messages: | 264,596 |