E-lecktrickle question.

[DICKEYBIRD]

I received my eBay KBIC-120 speed controller (thanks Max!) and it's sittin' there on my workbench begging to be tested. Once it got here, I confirmed that I needed to order a plug-in resistor for 1 hp use and a 5K pot.

I ordered them from a large eBay store and received the pot today but instead of the resistor, I got a plastic bag with 3 pieces of hard candy and a piece of bubble gum. That really added to the allready unhappy experience I had with them. The store's website looked like it said "Eligible for combined shipping" but when I ordered the 2 parts, I got tagged for $10 each shipping. I called and the lady said "Sorry, you have to order another of the same part number to combine shipping." $20 shipping for $4.47 in parts. Should'a read the fine print I guess.

Anyway, I want to see if the control works now that I have the pot. It should be OK to hook up the motor and run it up to half speed or so with no load even though the existing resistor is for a 1/2 hp motor, shouldn't it? If not, how about using a big spotlight bulb as the load? Looks like I have to wait another 5 - 10 days for the resistor to come in.

[MotorradMike]

Did the candy have any connectors on it?

Seriously, I don't know anything about your controller but if you require a .01 Ohm resistor, light bulb won't be anywhere that low.

This is one of those "Wait 'til you have all your ducks lined up before you smoke test it".
You will kick yourself if you break it.

[squirrel]

I received my eBay KBIC-120 speed controller (thanks Max!) and it's sittin' there on my workbench begging to be tested. Once it got here, I confirmed that I needed to order a plug-in resistor for 1 hp use and a 5K pot.

I got a plastic bag with 3 pieces of hard candy and a piece of bubble gum.

That is a derogatory gesture practiced by some ebay sellers.

[DICKEYBIRD]

That is a derogatory gesture practiced by some ebay sellers.

Yup, especially the ones from Noo Joisey.

[gaston]

That sucks! I understand its a common ebay seller practice to make a profit on the shipping so they don't have to pay ebay the "pound of flesh" they get for their cut. You think they would at least do a good job of packing for that money!

[DICKEYBIRD]

....if you require a .01 Ohm resistor, light bulb won't be anywhere that low.

You will kick yourself if you break it.

Definitely! That's why I was hoping to get some of you guys' expert input. I don't want to wait too long to try to send it back if it's tango uniform out of the box.

It came with a .025 ohm resistor installed (for 1/2 hp motors) so I didn't intend to use the lightbulb to emulate a .01 ohm resistor. I was thinking the bulb (or bulbs) might simulate the load of a motor...enough to see if the control works. If it gets bright/dim as the pot is turned up/down, it's working, right? I wonder how many 100 watt light bulbs is 1/2 hp?

Then again, it ain't supposed to be a light dimmer so maybe I better just wait.

[MotorradMike]

OK, I do know that 1HP is 746 Watts so exactly 3.73 100W light bulbs make a 1/2 HP. Thought you had a 1HP motor.

I read a bit more on the KBIC site and see that the resistor is meant to keep the controller operation consistent even if you change motors so maybe it's not a big deal.

Still, I'd try to resist screwing with the first one until you get a feel for reliability, stability etc. Maybe it's solid as a rock, maybe it's fussy about some things.
I don't know.

Run video if you try it!

[Black_Moons]

Just wait to test it -_-;

Also, Iv NEVER heard of 'combined only with same part number' shiping.
Id complain to ebay. And wtf at candy. Sounds like they just tryed to slap something in the package so you did'nt whine about it taking forever to ship because they don't have the part. Leave negative feedback after you get the proper part :P

[whitis]

You should be able to run the motor with no braking resistor provided that you disable braking in the VFD setup. You should be able to use the braking resistor you have, provided you configure the maximum braking amps to be less than what that resistor would draw when connected across the capacitor bank (rectified AC line voltage or about 1.414 times the RMS line voltage); you will get braking, just not as much as with a resistor sized for you motor. You should also be able to rely on the units internal protection even without these configuration changes but check your docs.

If you brake the motor, the VFD will probably (designs can differ) take the energy from the motor and put it into the capacitor bank. This process is not limited to the voltage the motor generates open circuit driven at full speed (which will be approximately the nameplate voltage). This causes the voltage on the cap bank to rise which will ultimately destroy the control or the motor winding insulation unless the energy is dumped into the braking resistor or braking is abandoned. The VFD will hopefully disable braking when it notices this voltage rising to prevent this. However, this happens very fast (milliseconds). The capacitor bank should be sized large enough and the VFD checks the voltage frequently enough that a missing (or bad connection) on the braking resistor does not cause bad things to happen. So, with a properly designed VFD and no defects in the sensing circuits, the VFD should survive without the braking resistor, you just won't get braking.

[MaxHeadRoom]

This is a SCR drive so there is no capacitor bank, it should be fine to test with the existing resistor as long as you do not load the motor or try fast accel/decel, and use an appropriate fuse in the unit.
The resistor is there as a current sense for the current limit circuit which incidentally also has a POT that can be set for overcurrent.
As I mentioned earlier, if you have a motor supplier near you that sells Baldor products, they will have the resistor as Baldor relabels the same drives.
Max.

[alsinaj]

A resistor in that range of resistance can be made out of a length of copper wire. Look up "copper wire resistance calculator" on the Web.

[J Tiers]

Dickeybird: I think I have a bunch of those somewhere, if so, and I have your address, I'll stick one in the mail......... They were leftovers from a product.

Copper wire tends to change resistance, real resistance wire does not change much. And measuring low resistances can be a problem, although there are some "cheatin shortcuts".....


Found 'em...... similar to this, 5W rating. Yours for the address. PM me.

http://www.bourns.com/data/global/PDFs/PWR4412-2S.pdf

[DICKEYBIRD]

I finally got a little time in the shop today and decided to hook the thing up to the motor and see if it would work. Kind of anticlimactic actually. It just spun the motor smoothly from a crawl to 5700 rpm without complaint and did a good job of regulating the speed when I grabbed the motor shaft and tried to slow it down. I now see why they're a popular piece of equipment.

Funny, I ran it for quite a while at 1/2 to 3/4 speed, squeezing the shaft as I could to add a bit of load and it didn't even begin to feel warm. I'll bet it would do the work I need it do without a heatsink or the proper resistor.

[MaxHeadRoom]

With the resistor you have for a smaller motor, means a larger motor could go in to current limit earlier.
Which is better than the other way around!
Max.

[J Tiers]

Your resistor is in the mail. You get to make the little pins to fit the plug-in socket, though.