Why do VFDs Need Special Cables? | Ask Al Presented by Quad Plus

Care must be taken in selecting VFD cables because of the direct impact from electrical noise interference. Longer term impacts are also much more expensive to mitigate as they typically result in down times from potential replacement of cables and motor repairs.
If you are experiencing issues related to motor cabling or if you are need support in cable selection, give us a call at 1-877-870-QUAD or email us at [e-mail].
For more details, read the full blog at quadplus.com/vfd-special-cables
or for information on vfd repairs, visit us at www.quadplus.com/vfd-repair-s...

[@garbo8962]

I retired from a large campus that had over 500 VFD'S. Never wasted money on shielded cable on there 480 volt output side of any drives. Used plain Jane THWN copper wire for every 6 & 18 pulse drives. Most motors were plain Jane NEMA motors & the rest high efficiency motors. Had some 40 year old motors that were on drives. Even had two 4,160 volt 1,750 HP chiller motors on drives with regular medium voltage cable. Most drives were less then 40' from motors.

[@KLAWNINETY]

I'm pretty sure the MV Cable confers the same advantages as VFD cable because it's also shielded

[@Jay-fp8iy]

Excellent video except you kept saying XPLE instead of XLPE towards the end of the video. Thanks for the explanation fantastic information

[@staninokla]

Thank you Al. You are more important to us than you will ever know.

[@apdahlen5282]

Thank you Al,
Excellent introduction to cables.
Best Wishes,
Aaron

[@stemmachines6446]

Very good information and explanation. Thank you.

[@vanjka39]

Thank you for the information, boss

[@glasser2819]

this is a brilliant presentation, thank you.
The only thing I would add is that conductors need to be SIZED TO PASS THE PEAK CURRENT density, not the average value.
This helps transfer the dV/dT spikes into the motor without dissipating energy in the serial impedance of an undersized sized cable. (ppl talk about reflecting or bouncing waves when energy can't go through!)
This is is true with any Pulsed Modulation: "pass the peak not the average"!
🤞

[@peterc7696]

Great information, but I note Belden does not recommend the use of 360 degree shield terminating cable glands. With a shieled terminating gland, significant shield currents can be released, for example at enclosure ingress, exposing sensitive equipment to noise currents that would be contained if an isolating cable gland such as a Crouse CGB, ADE or CMP TC or A2 Gland. Pete C

[@michaelnoble2432]

I don't know where you read that, but 360 bonding of cable screens at BOTH ends to the equipment chassis is almost always best for EMI. The old advice to bond only at one end was typically to avoid the potential for excessive currents to flow through the screen and damage them, but there are ways to address this concern.

[@michaelcostello6991]

Super video😊

[@qzorn4440]

Geee, build the vfd power pack on the motor back-end or very close to the motor, then no more long cables... sorry belden...:) or go back to the one common line shaft or adjustable gearbox

[@robertmunga2630]

Should be XLPE (Cross Linked Polyethylene)?

[@handdancin]

what would i start with to learn about this general area? something more specific than "electrical engineering"

[@yuriycas1719]

very informative, but one question - doesn't the motor act as as smoothing inductor (reactor) and smooth out the square wave at least somewhat in the entire circuit?

[@vfdcode]

You're asking, will the motor’s inductances do the same job as an output load reactor? The answer is absolutely not. The output load reactor is placed next to the drive. This slows down the rise time before it even gets to the cable. This helps in many ways and if you'd like to know more, I can tell you. You might not believe this but smaller motors have more problems with pulse width modulation then larger motors when you are running long cables. If you'd like to know, just ask.

[@michaelnoble2432]

Sort of. What the motor inductance DOES do is smooth the motor CURRENT so that it approximates a sinewave, despite the VOLTAGE being a PWM mess.

[@Dlewis0901]

Slide says LGBT instead of IGBT at 0:48

[@tilliesinabottle]

maybe all along it was just a lowercase L, and we've all been misreading it

[@SCfalconry]

" I " for Insulated
" L " is for someone on the crew has a sense of humor.
ROFL.

[@primi22]

It’s the newer type Lesbian gay bipolar trans-sister

[@mitskiR]

Volunteer fire Department

[@jamesinman3414]

Was he even speaking English? #iamdumb