VFD break
VFD break
(OP)
Dear colleagues,
I design an application where railcars are positioned over a loading bunker with an electrical winch. The question is if i use a VFD do i need an electromagnetic break for the motor to stop the railcars or the VFD can meed this functionality too. The breake is used only to slow down the railcars not to hold them.
I design an application where railcars are positioned over a loading bunker with an electrical winch. The question is if i use a VFD do i need an electromagnetic break for the motor to stop the railcars or the VFD can meed this functionality too. The breake is used only to slow down the railcars not to hold them.





RE: VFD break
Wait for our VFD experts to discuss the configuration of the VFD.
Bill
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Jimmy Carter
RE: VFD break
RE: VFD break
Remember that braking requires hp or kw just the same as motoring so your motor and drive must be sized large enough for whichever is larger. And, of course, the braking resistor set must also be sized for the braking kw.
If you don't require a precise ramp time to zero, it might be cheaper to use DC injection braking. Most VFD's come standard with that capability and you wouldn't have to buy the resistor set.
Be careful about doing motor braking thru high ratio gearing. Some gearboxes will not transmit negative torque but will, instead, lock up (as in worm gears over 28/1 ratio). If you have that kind of power train, you will not be able to use the motor to stop the railcar.
RE: VFD break
RE: VFD break
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RE: VFD break
RE: VFD break
jaref does a Regenerative Drive needs additional equipement besides VFD?
RE: VFD break
RE: VFD break
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RE: VFD break
Correct on how CT implement regeneration. I think economics would weigh against this in a single drive application, but in a multi-drive system with a common DC bus it might actually be favourable.
This link might be of interest. http://ww
I've never used this drive family in regenerative mode, but as a product line they were pretty good: a lot of capability at a reasonable price. Not sure what effect, if any, the Emerson takeover has had, although generally I find Emerson's products to be toward the top end of the market.
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RE: VFD break
Lectricwes, thanks for the advice i will ask for a electomagnetic brake for the motor as a fail safe solution in case of a power drop.
RE: VFD break
ABB loves that however, because I move them to that solution and it's a lot more expensive and complex: better for me.
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RE: VFD break
RE: VFD break
A brake resistor set for this application would be rather inexpensive and the energy would probably not amount to enough $ to save either. A simple motoring drive with a snubber resistor package might be the most economic choice.
It deserves a look, anyway.
RE: VFD break
just to pick up on your comment about Siemens regenerative units.
The PM250 range of the G120 range is regenerative but is not an active front end; it uses IGBT's but with two comparators sensing the +/- phase to turn the IGBT on/off. Not actively controlled via a PWM gate circuit.
Siemens do have higher power Active Front End drives up to the MW range. This would be covered by the G150.
Having said this, I agree with DickDV. For 30kW and 10% braking duty, I would use a brake resistor based system.
RE: VFD break
RE: VFD break
Here is an article interview with another company than was mentioned above, but it generally covers what you asked, and has benn answered. Just a little extra support.
http:/
RE: VFD break
Welcome to the Forum! I see you're relatively new here, so just FYI that "hesya" website you linked to is nothing more than Chinese plagiarizers of Eng-Tips! So that entire thread actually took place in here, they just copied it and made it look like their own. They vex the Eng-Tips management but have that "Chinese immunity" meaning that since our government owes so much money to China, they are toothless to do anything about the copyright violation.
I know you didn't know, but in the future if you come across that site with Google, realize that you can also find it in here in it's original form.
Keep coming back!
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RE: VFD break
Thanks. I DID notice the two had a particularly simular look to them, only that this one looked nicer. I thank you for the information. I've been reading on here on and off for over a year, but finally decided to put in a few cents. So good to know. I appreciate it.