Spindle Motor Fan sound is annoying!!

[CNC Viking]

Hi,

I think I am not the only one that hates the Spindle Motor Fan's sound as soon as you flip the main power switch. It starts even before I start the NC and the spindle motor itself is running. I think this is unnecessary if I only want to do some work on the machine without the need to run the spindle.

The fan is a 220V AC unit and is mounted at the top of my 5.5 / 7.5 kW Mitsubishi spindle motor. I would like to control the fan by a relay that use a signal from the Spindle driver. I want the relay to make contact when the spindle motor starts, hold the contact while the spindle runs and after the spindle is stopped, continue to hold contact for the fan for another 15-30 min. ( I want to use one of those bathroom fan electronic thingy's for the delayed fan stop function).

Can anyone experienced with spindle drivers help with info about which signal to use to activate the relay. I do not want to experiment myself and thereby risc to ruin my driver.

[CNC Viking]

Waky, waky... Electrical Guru´s!

This is a piece of cake for you.

Come on, tell me how to activate that relay.

[onthebumper]

There is no output from the drive to say that the motor is running or not running. Even if there was I wouldn't mess with it. You might end up damaging the drive trying to wire it up and what seemed like a simple project would turn into an expensive fix for a down machine.
Your best bet would be to modify the PLC to create an output from the CNC when the spindle is running. Good luck finding someone with the expertise to do this type of modification though.
I realize that it is annoying but all machines run this way, even the ones that are currently being sold.

[CNC Viking]

onthebumper,


I agree and will leave the PLC alone.

What about placing a coil around one of the spindle motor's power wires (pretty much like a Clamp-On AMP-meter) and then hook this up to an OP-Amp that then could activate my relay? There must be a lot of clever low cost hobby-gadget devices out there. I just need to know what components to look for.

I'd rather do something like this instead of using a thermistor at the motor.

[H.O]

Hi,
What kind of documenation do you have on the control? Do you have schematics on how the spindle drive is interfaced to the control? Is it an analog speed reference and a forward/reverse signal or is it all digital interface with some form of bus and protocol like Profibus, Modbus or whatever.

The current sense idea you have might be worth a try. Then you can play with that circuit first, getting it do what you want without actually "cutting" into the machine.

Another thought is to tap of the feedback signal from the spindle, there's probably a lot of different ways to acomplish this. The easiset though would be to just tap of the "start" singal going fromn the control the drive, if that signal is accessable. However, without knowing exactly what you're doing it might cost you more than it's worth...

One thought though...are you sure that the control doesn't monitor the fan? I mean it might throw an error if the fan isn't running....

[Geof]

Install a microswitch to control the fan that is open when the spindle is at the home position and closed when the spindle moves down?

[Al_The_Man]

Originally Posted by CNC Viking What about placing a coil around one of the spindle motor's power wires (pretty much like a Clamp-On AMP-meter) and then hook this up to an OP-Amp that then could activate my relay? .

That is one least invasive ways, a ready made device that does this is the Honeywell CSDA1DC, (see PDF), if you have 24vdc available you can feed this and a small 24vdc relay and you should be able to get what you want.
What they show as a 'Flux Collector' is just a couple of turns of wire, you may not need it, and just thread one of the phases through the hole in the device.
BTW, if this is a Mitsubishi 500 or 50 controller, the PLC can be programmed at the operator panel.
Al.

[CNC Viking]

H.O,

It is a Mitsubishi "S-Analog Spindle Drive Unit" with a bus.


The only signal I could see that varied was the AC Voltage between the drivers' 3 motor phases U, V, W. It was 0V at standstill motor, 10V AC at 50 rpm and rose as I increased rpm. I did not check voltage at full rpm because it was not warmed up, but it was near 200 VAC at around mid range.



The connections page in Mitsubishi's PDF Manual BNP-A2993-24. I have the whole document and if anyone is interested I can mail it (19MB).




The control does not monitor the motion of the fan. I could run the spindle both manually and by drip feeding a program with disconnected fan fuses.

However, the spindle motor does have an over-temp sensor that alarms when motor heat is above the safe limit.


Geof,

Not a bad Idea, but I would like the fan to run at all times when spindle is running just to be on the safe side.



Al,

I downloaded the Honeywell PDF. The Spec drawing looks very much OEM to me = must be a lot of $$$. Where can one get those devices? To be honest, I have not Googled the PNo's yet.

But hey, wait a minute! My control is a Mitsubishi Meldas 520 AMR!
How, exactly, can I program the PLC to start the spindle motor fan? There must be unused relays on the I/O board for this I guess? Please tell me where to find the place in the menu's and what parameters to use etc.

[Al_The_Man]

Originally Posted by CNC Viking Al, I downloaded the Honeywell PDF. The Spec drawing looks very much OEM to me = must be a lot of $$$. Where can one get those devices? To be honest, I have not Googled the PNo's yet. But hey, wait a minute! My control is a Mitsubishi Meldas 520 AMR! How, exactly, can I program the PLC to start the spindle motor fan? There must be unused relays on the I/O board for this I guess? Please tell me where to find the place in the menu's and what parameters to use etc.

If you look in the I/O diagnostics the Xxxxx are inputs and the Yxxxx are physical outputs.
With the integrated Spindle, it is unlikely that any external outputs are picked up with the M3/M4.
http://www.meau.com/Files/BNP-B8368-23.PDF
The device in question is around $20.00 here, if you have access to Honeywell items, it is a common part.
A typical use is to detect arc current presence on Plasma machines etc.
Al.

[HuFlungDung]

Perhaps it would be better to seek out a quieter fan. Using the search terms in google
axial fan low db
brings up a few possibilities.

Also inspect the fan currently on the machine for bent or missing blades which could induce noise and vibration.

[CNC Viking]

Al,
Thanks for the link to the manual. Well, I must say this is a bit of greek to me.

I went to the Diagnostics , PLC-I/F part of my Meldas control and found this:


I also checked the manual from page 16 through 118 trying to get some clue(s).
But, frankly, I wouldn't know what to do and where physically find a signal.


As for using the Honeywell current sensor:

I also found this additional info about the sensor you described.


Al wrote:
"If you have 24vdc available you can feed this and a small 24vdc relay and you should be able to get what you want.
What they show as a 'Flux Collector' is just a couple of turns of wire, you may not need it, and just thread one of the phases through the hole in the device."

So I only need 24V DC to run this sensor and it will output a 24VDC signal to activate my relay?

I also found this source with more sensors. Click between 5 pages at right top corner. Any of those that I can use?
http://se.farnell.com/jsp/search/results.jsp?N=1004254

HuFlungDung,
Might use that idea as plan B maybe. The existing fan is of course checked, cleaned and runs smoothly. My machine only has 1700 spindle hours so far. It is just that it makes a heck of a blowing sound.

[CNC Viking]

The answer was right in front of me... Duh!

I am using the 24VDC signal that lights up my "SPINDLE CW" button whenever the spindle runs. The signal is used to pull a small relay that activates a fan timer which in turn powers the fan. When the spindle runs in M3 mode, the light is on and it immediately starts the fan. When the spindle is stopped, the light is off but the fan continues to run for another 7 min or 15 min (you can chose in the fan timer).

The only worries I have is: Will the relay coil's current load pose any threat to the circuit that drives the 24V lamp? I will actually measure the current tomorrow. Cant be much.

Otherwise, everything worked perfect and according to my intentions when I tried it tonight.

See that button "SPINDLE CW"?



I use this 24VDC relay to power the spindle fan via the Velleman VM154 fan timer.



The Velleman VM154 fan timer. It can be powered by 110-230VAC and max load is 3A.
My system and fan is 220VAC.



Finished installation in the electric cabinet. Velleman timer on the floor.