Variable Frequency Drives VFD's for spindles

A question to kick off this topic....

The MO1, MO2, MO3 multifunction photocoupler outputs of the Delta VFD-B can surely drive Solid State Relays (SSR's) directly....

I have some Crydom D2W202F SSR's. Input spec is 3-32VDC, 1500 ohm, typical input current 3 mA, turns on at 3VDC, turns off at 1VDC.

The Delta Manual says max output 48V DC, 50mA. Could I drive those Crydoms from it? Would I need a "dropping" resistor? (about 4k7 ?)

Gerald,

Page 2-23 in the VFD-B manual shows a better connection diagram than page 2-14. It looks like the M01, M02, and M03 share a common ground (MCM). It also looks like they SINK current. To make things really simple, I would connect 5VDC to one side of a 1/4 watt resistor, either 330 ohm or 470 ohm (either would work well). The other side of the resistor would be connected to the + (positive) control input on the Crydom SSR. The - (negative) control input of the Crydom would be connected to M01, M02 or M03. The MCM on the VFD would be connected to the 5vdc supply's GROUND. When the M01, M02 or M03 is turned on, it will SINK some current through the Crydom SSR, thus turning on the Crydom's internal photo diode, which will activate the SSR. Whatever is connected to the 'business' side of the SSR will do its job.

Most SSRs that I've used drop about 1 volt, or so, across the internal photo diode, so a 330 ohm or 470 ohm 1/4-watt resistor gives you about 10ma to 12ma of current without producing too much heat.

After posting, I looked at page 2-12 one more time. It looks like the outputs are already assigned a default use by the factory. Since I'm not in my shop, I can't look at my unit, but I would imagine that you would just disconnect and tape off any wire that is connected to the M01, M02, or M03 outputs.

Hi Mike, thanks for looking at this. My manual (both original and downloaded pdf) only has 2 pages in Chapter 2, while Chap. 3 has 17 pages. I can't find the diagrams you mention. But I do now understand the sink situation. Thanks.

I found the manual at http://www.delta.com.tw/product/em/a...tor_manual.asp

(My manual is tucked away inside the Alpha's door pocket so I won't loose it - which means that it's easier to read the manual on-line than it is to crawl under the machine to fetch the paper manual.)

That's a later edition - October 2005. Yes, much better pictures and descriptions all over the manual about other things too. Thanks!

ShopBotters seem to mostly have the Delta B-Series. I also bought a B-series and have been quite happy with it.

Delta VFD-B

Now when I have wanted a second VFD, the local stockist of Delta asked if I really need a B-series, or if the M-series would do? They told me the woodworkers use the M's while very technical applications use the B's. M is always in stock a mile away from me while the B's are special order from 1000 miles away. M is cheaper. Meant for in-panel mounting (doesn't have round holes for cable glands)

Delta VFD-M
(25mm narrower - the keypad is tiny!)

Have since bought a VFD-M for 3-phase (and another VFD-S for single phase). The in-panel mounting appeals to me because the chokes/reactors can be mounted there too. The mini-keypad has a potentiometer on it and the keypad has screwholes for mounting on the front panel of the housing.

[J.R. Hatcher]

I've heard it is ok to power a motor with a VFD that is rated for more hp than the motor. My question is, what happens if the motor hp is more than the VFD? My motor is 1.5 hp my VFD is rated for 1 hp.

[gixi]

I place an order from this chinese seller on Ebay and in 20 days the items should arive in Romania. All the prices are more than good.
This is the adress on Ebay: http://stores.ebay.com/linearmotionbearings

[javeria]

G' do you remember what wire size (sq mm) you used for the input of the Delta VFD - I have a M series(2.2KW) - the data sheet calls out for 27A @ single phase and 12.5A @ 3 phase power - and since I plan to use a single phase - it also calls out to use 8sq mm wire?

What about your's.

I have plenty of 3 sq mm wire with me.

RGDS
IRfan

[Gerald D]

I am quite far from there now, but all single phase circuits at my premises are protected by 20 Amp breakers and 2.5mm² wire is common for that. A 230V circuit consuming 20 Amp is roughly giving 4600 Watt or 4.6 kW. A 2.2kW VFD is comfortable with 230V supply, 2.5mm² wire and 20 Amp circuit breaker.

I think you are confusing some numbers for 115V supply, and taking the wire size from the max size allowed for the terminals.

[J.R. Hatcher]

Any suggestions where I may find the answer to my question in post #7 would be greatly appreciated. Thanks

[domino11]

JR,
I would suspect the VFD would either shut down, limit the output or cook. Depends on the VFD make and protections it has. The VFD is like a switching power supply it can only deliver so much power.

[Gerald D]

Originally Posted by J.R. Hatcher

I've heard it is ok to power a motor with a VFD that is rated for more hp than the motor. My question is, what happens if the motor hp is more than the VFD? My motor is 1.5 hp my VFD is rated for 1 hp.

Your 1.5HP motor is only 1.5HP when you put a 1.5HP load on it. In other words, it is a 1.5HP capable motor. A 1HP capable VFD will happily get that motor spinning and feed loads on that motor as high as 1HP. Then you can program your VFD to either trip out, or give you an alarm first.

(But you cannot use 1HP VFD for a 100HP motor, because it won't handle the huge inrush/startup current.)

I have run 3.2kW spindles on a 2.2kW VFD. It made no sense for me to buy a smaller spindle to run on single-phase because the cost-saving is too small.

[J.R. Hatcher]

I put this 1.5 hp 3450 rpm motor on a new to me Delta drill press. It is variable speed belt driven. It came with a .75 hp 1725 rpm motor. So I plan to use it in the lowest speed setting and use the VFD to adjust the speed up and down. I don't think I will ever need all the power from the 1.5 motor. Thanks Gerald ...... that's just what I wanted to hear.

The VFD is a Allen Bradley PowerFlex 40 Cat No. 22B-B5P0N104

[Gerald D]

You might be surprised JR . . . . .

With the original .75hp motor, and the belts set for lowest speed, say 575rpm spindle speed, one third of motor speed, the spindle torque would be triple the motor torque.

Using a VFD to bring the speed down, you do not get the torque multiplier effect that you would have had from belts. For really heavy duty low speed work, best to still change the belts.