ECM evap motors running backwards after a power surge.?

[kengineering]

We've been using Wellington ECM fan motors for a while now with no issues. Now a customer calls a claims that if there is a power surge his meat case fans reverse themselves. Has anyone had issues of this nature with this type of fan? Is it even possible. Mfr. says no but Just putting it out there. Thanks, Ken

[chemi-cool]

Are they DC?

[Brian_UK]

Do they all reverse or just some of them?

If just some then perhaps they are just not running but being spun by the airflow of the ones that are running.

[kengineering]

Well thanks for the replies. let you know when i find some new evidence. Phones been quiet today. LOL.Ken

[TERRENAS]

Do they all reverse or just some of them?

If just some then perhaps they are just not running but being spun by the airflow of the ones that are running.

Even so they should turn around in the same direction, not in reverse...
I suppose they can run in reverse if someone changed some conections...

[Josip]

Hi, TERRENAS

Even so they should turn around in the same direction, not in reverse...
I suppose they can run in reverse if someone changed some conections...

You are quite sure?

I'm

Best regards, Josip

[cadwaladr]

not too up on electrics,but had a 3 phase cond motor do it my mate who is more up to speed said it was known as ghosting,way beyond me i just treat elctrickery with the utmost respect.

[hookster]

not too up on electrics,but had a 3 phase cond motor do it my mate who is more up to speed said it was known as ghosting,way beyond me i just treat elctrickery with the utmost respect.

I was on the opinion as with the other posts about client issue but cadwaladr got me thinking about "ghosting" or stray voltage and with an ECM fan depending on wiring of course the possibility that the fan controller sees stray voltage via its PWM input which if it was earth leakage would be more negative to reference. I do not think it is impossible to commutate a synchronous motor in the reverse direction as manufacturer states.

Maybe try improve earthing arrangment or voltage regulation to fan controller.

[PaulZ]

Hi Terrenas
Brian is correct.
When there are multiple fans on and evap and one fails the others will suck air in through this fan (air will take path of least resistance) and because the airflow is reversed the direction of rotation of the fan will be reversed.
This has caught out a lot of inexperienced people and will continue to do so i would suggest.
Regards
Paul

[nike123]

Here is description from Welington:

ECM Technology

Types of electric motor differ largely in how they achieve the interaction of magnetic fields, and most importantly the field reversals, necessary to make the motor turn. Electronically commutated (ECM) motors are brushless DC motors where the direction of the electric current is switched using electronic controllers. As the switching of the current is technically known as "commutating”, brushless motors are also called “electronically commutated” motors.

I would say yes, it is highly possible that power surge makes electronic circuitry to change direction of fan rotation.

[nike123]

Are they DC?

Yes they are!

[nike123]

Second part:

[NiHaoMike]

Try adding some capacitors to the power supply rails.

Modern inverter drive ("ECM" or "brushless DC") motors are very sophisticated inside. Many modern implementations, such as Delta's Cindy Wu sensorless FOC (used mostly for cooling high performance computers), dispense with the resolver altogether and replace it with a single chip computer to derive the rotor position and hold the stator flux 90 electrical degrees ahead of the rotor, where the efficiency is the best.

[nike123]

Rotation Sensing


The first time the Evergreen EM is powered up and receives a signal on
one of the Low Voltage Signal terminals, it will perform a Rotation Sensing
process. With this feature, the motor will automatically determine the proper
operating direction of the blower wheel by running the motor for several
seconds in each direction.
Do not turn off the “High Voltage Power” or the “Low Voltage Signal inputs”
to the motor until the motor continues to run in one direction. During Rotation
Sensing, the motor will run in both directions, up to four times if necessary, to
determine the proper operating direction. If the proper direction cannot be
determined after the forth sequence, the motor will operate in the default
direction of counter clock-wise (CCW).
Once the motor continues to run in one direction, Rotation Sensing is complete
and the feature is locked out. The motor will continue to start and run in this direction
without performing Rotation Sensing even if the High Voltage Power is disconnected.
If the final operating direction of the motor is not the proper direction for the
blower wheel, go to the “Troubleshooting Guidelines” on page 14; “Wrong
Rotation”.

Page 11 here:
http://www.mediafire.com/?l75am5wahwvjkqw

[Grizzly]

Thanks Nike.
Brilliant!
Grizzly

[Rob White]

Rotation Sensing


The first time the Evergreen EM is powered up and receives a signal on

Snip

motor is not the proper direction for the
blower wheel, go to the “Troubleshooting Guidelines” on page 14; “Wrong
Rotation”.

Page 11 here:
http://www.mediafire.com/?l75am5wahwvjkqw

As usual excellent information.

I'd up your reputation if I didn't have to share my Luuuuuve around

Rob

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