24vdc fan motor problems

SHAUN · Post by **SHAUN** » Wed Aug 29, 2012 12:05 pm

HI GUYS

I HAVE BEEN TRYING TO GET THIS(SCREEN SHOT) FAN TO WORK FROM MY PDM USING A HV700 10BUTTON TOUCH AND POWERVISION2.3.11175
WITH NO LUCK, EVEN WITH OVERCURRENT ON 25AMPS.
EVEN WHEN I DESELECT OVERCURRENT SHUTDOWN (SCREEN SHOT),THE FAN WOULD JUST MAKE A SUDDEN NOISE, MOVE A BIT THEN STOP, LEADING ME TO ASSUME THE OUTPUT HAS TRIPPED.

WHEN I MEASURE THE STALLED OHM IT'S 0.6 OHM.
WHEN I MEASURE RUNNING AMPS IT'S 9 AMP.

PLEASE GIVE SOME ADVICE, OR TRY TO HELP.
AS A NEWBE I HAVE BEEN TRYING FOR 3WEEKS NOW, AND I'M VERY DESPERATE.

Post by **ksaenz** » Thu Aug 30, 2012 9:38 am

Hello SHAUN,

Here is some advice from someone who has more experience with the PDM:

Are you using the PDM app?

Make sure you are not trying to use and H-Bridge because it doesn’t work in the app.

Make sure the fan is on channels 11 or 12.

It is possible that the inrush current on the fan lasts too long.
I have not attempted to drive a fan but the current has to be down below the set circuit protection level within 150ms. Upon starting the fan, the motor is probably stalled for a lot longer than a typical load causing the fault.

Deselecting overcurrent protection will cause the PDM to retry the circuit autonomously.
I believe it will attempt a restart 5 times once a second. (this is assuming the app is working correctly). This is probably not enough to get the fan spinning reliably.

If you are using a single channel high side, and has it on channels 11 or 12.

You can try and use a soft start. Meaning, find a lower PWM value that works for getting the fan spinning and increment the PDM value up to the full 100%. This will take some experimenting to find a good starting point that doesn’t stall the fan too long possibly causing damage, but allows you to get to full power without so much inrush current that it trips the circuit.

You could try to set up a loop that starts at 30 or 40% and increases in 10% increments up to 100% every 500-1000ms. (again with the caveat that you can accomplish this within the app).

I hope this is helpful to you.

Regards,

ksaenz

ECS-SA · Post by **ECS-SA** » Thu Aug 30, 2012 12:27 pm

Hi All,

Shaun and i have tested it on window wiper motors aswell but have no luck the wiper motor does the same thing and i think it has something to do with the app i am not sure how to set it up with free form can to get the whole system to work correctly with all its outputs and inputs to work so if any one has suggestions please help us with this.

Thank you

Marcell

bmcrae · Post by **bmcrae** » Fri Sep 14, 2012 12:25 pm

Also the PDM is a 12 volt device and you are showing a 24V fan. Does the fan work down to 12 Volts?

SHAUN · Post by **SHAUN** » Sat Sep 15, 2012 3:04 am

HI GUYS

THANX FOR ALL THE HELP AND SUPPORT.

THIS IS A 24VDC PDM, ITS A NEW ADDITION TO THE RANGE(I HAVE HEARD)
USING THE LOOP FROM 20% - 100% WITH 50MS - 300MS HAS HELPED ALOTT THE FAN IS NOW COMING TO FULL SPEED AT THE END OF THE LOOP. NOT SHURE IF DOING THIS WOULD BE BAD FOR THE FAN,BUT AT LEAST IT TURNS NOW.

PLEASE REFER TO THE ATTACHMENT

DOES ANYONE KNOW WHAT COULD HAPPEN TO THE FAN IF THE VOLTAGE IS REGULATED LIKE THIS?
DO'S AND DONT'S WHEN CONTROLLING FANS PROPORTIONALLY?
E.G. UDJUSTING FAN SPEED ACCORDING TO THE COOLER TEMPERATURE?
AND HOW WOULD ONE MONITOR THE AMPS OR WATTS?

THANX AGAIN

SHAUN

alb · Post by **alb** » Thu Sep 20, 2012 3:25 pm

Can you show a screenshot of that script or state machine programming? HV700 configs don't load in my configuration studio without that extension.

alb · Post by **alb** » Thu Sep 20, 2012 5:51 pm

My wiper motor on 24V PDM CH12 appears to draw 4-5A once up and running on high speed. ~1A on low speed. Even with overcurrent shutdown disabled, CH12 output regularly shuts off, then immediately resumes. The wiper motor completes a few revolutions normally, then, miss a few beats while the output shuts down and comes back up. Very Unstable. Very unusable.

SHAUN · Post by **SHAUN** » Mon Sep 24, 2012 1:16 pm

Here are some screen shots.
thanx for replying, i hope this helps.
I HAVENT BEEN ABLE TO STABELISE THE STARTUP SEQUENCE, IT IS A BIT JITTERY.
I HAVE HOWEVER BEEN ABLE SEETHE AMPAGE:
THE MOST RECENT PROJECT WE DID HAD 2 FANS ON 1 PDM, FAN 1 USES +- 8AMPS WHILE FAN 2 USES 9AMPS, BOTH AT RUNNING, BUT THE SENSORS GOING TO THE ANALOG INPUTS ON THE PDM HAD A BIG V DROP EACH TIME A FAN WOULD START UP, FORCING ME TO INSTALL A BODY SOLONOID AT THE END.

IF ANYONE HAS SOME INFO ON HOW TO ISOLATE OUTPUTS FROM EACH OTHER ON THE PDMS IT WOULD BE VERY MUCH APRECIATED?
DO PDMs EVEN HAVE THIS ABILITY AT ALL?

BECAUSE OF THE OVER AMP FEATURE OF THESE PDMS, IT WOULD BE NICE TO ELIMINATE EXSTA COMPONENTS LIKE BODY SOLONOIDS, FUSES,FUSEHOLDERS, RELAYS ETC.

WITH SOME HELP FROM MARCELL,I HAVE BEEN ABLE TO OPERATE A SMALL SIZE WIPER MOTOR WITH SIMPLE ON OFF STATE MACHINES, ALSO IN BIDIRECTION USING H-BRIDGES.
DOWNLOAD SCREENSHOTS RAR FILE.
HOPE THESE CAN HELP.

REGARDS
SHAUN

alb · Post by **alb** » Mon Oct 29, 2012 3:14 pm

The error in my ways was wiring two PDM outputs (park and high) to a common circuit (wiper motor). This appears to create a short between the active PDM output and the inactive output, or befuddle the circuit protection, rendering both outputs to that circuit unusable.

It sounds like we had different problems, however, to all PDM users, the same general caution applies:

If your fan motor, or any motor, has high and low speed windings, and you wire those to (2) separate PDM outputs, you will constantly trip the circuit protection and the motor will be difficult, if not impossible to run.

24vdc fan motor problems

24vdc fan motor problems

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