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+--- Thread: VFDs (/thread-1997.html)
RE: VFDs - EdK - 02-15-2014
Steve,
Now that it's the weekend, I'll find some time to look into this and see if I can help.
Ed
RE: VFDs - stevec - 02-15-2014
Thanks Ed, take your time, I'm in no rush. Shop time is very limited here due to the temperatures. Eventually I'll make sure my round column mill drill can fill the gap while I redo the "drive" of my Tree mill and install the vfd .
More #@%? snow on the way tomorrow, I'll be busy getting my share of fresh air.
RE: VFDs - EdK - 02-15-2014
(02-15-2014, 06:45 PM)stevec Wrote: ...
More #@%? snow on the way tomorrow, I'll be busy getting my share of fresh air.
I know what you mean Steve. I got some "fresh air" today because of that falling white stuff and they're forecasting even more on Monday.
Ed
RE: VFDs - Hopefuldave - 02-18-2014
I like ABB manuals, translated from the Nordic to English by someone who speaks BOTH languages well!
Mine's set up for 10, 25 and 50Hz fixed speeds on a switch (bit of diode matrix to get the right inputs) and 5-80Hz variable, the big BTH motor in the Holbrook's balanced well enough to stand a 2p coin on edge at 80Hz / 2500 spindle rpm full chat (with nowt in the collet) but I've wired a relay to one of the VFD outputs for an additional 240v cooling fan to switch off above 40Hz, as at low speed the fan won't push enough air to keep it cool... Wiring it that way (using the normally closed contacts, active 'above supervisory frequency' in ABB lingo) means the fan runs when stopped / VFD powered-off too, so it cools off between operations unless I isolate the machine.
Most VFDs have a few relay outputs and parameters to select what they mean, another one switches the suds VFD on and off with the motor, that's very handy! There are usually lots of meanings you can assign to the input (control) terminals too, fixed speeds, jog input, different motor.parameter etc., and more than enough for acceleration/deceleration rates, flying start (useful on a multi-speed motor), v/f curves etc - I was a bit daunted by the ABB book, and that's in GOOD English!
When setting up there's a parameter for nominal frequency, this is the point where the full line voltage is applied and it goes constant-hp - you can set it anywhere in the range, but too low and you'll risk over-current in the motor, as the back-emf is proportional to supply frequency - don't go below 45-50Hz on a 60Hz motor or you could cook it!
RE: VFDs - stevec - 02-18-2014
Thanks Dave, I'm digesting information as I go. I'm not in a hurry and I have the original 3 ph motor on the test bench hooked up to the VFD and I'm planning to set up my tachometer so I can see what speed the motor is actually turning and if it's the same as my VFD tells me.
I'm working mainly in the basement "woodworking" shop these days as heating the machine shop from stone cold takes longer than my will to work there lasts.
[attachment=7757] [attachment=7758]
I don't see much chance of adding a cooling fan as the motor's totally enclosed.
The nameplate specs are pretty illegible if needed I can take a better shot.
RE: VFDs - EdK - 02-18-2014
Steve,
Does the nameplate list the insulation class?
Ed
RE: VFDs - stevec - 02-18-2014
Ed, I'll check.
RE: VFDs - stevec - 02-18-2014
Ed, here's what I got from the plaque
Type C 000
Frame AFO-9125
Model 3971x218
Ser. No. 663164A-8
PH. 3 time Rtc Cont
CY. -60 oc
rise 55
ins. sys A Code K Design B
HP 1.5 surprise to me , I thought it was 3 hp
RPM 1800
Volts 220/440
Amps 4.8/2.4