Can I mount my vfd inside the mill column or would it overheat?

[mksj]

Having done 100's of VFD installs, almost all these have been in sealed metal cabinets, I have yet to see a VFD over heat and this is w/o a an enclosure fan. The VFD's are directly mounted to the back plate or cabinet to aid in thermal dissipation, can't say I have ever done an install or seen a factory install with rubber mounts. Better quality VFD's are designed for a wide range of environmental conditions, follow the manual. As already mentioned, if you are running the VFD hard for extended periods of time then an auxiliary fan may be warranted, but not in this case. If you decide to have 120V say for sockets then you need 4 wire power in and should have separate breakers at the machine specific to the load and wiring foe each circuit.

High pitch wine is a function of the carrier frequency and how it is modulated, some VFD's vary the frequency to decrease the tone (whine) and also dynamically adjust it based on operating conditions/load. I use Yaskawa VFD's and they have no perceptual whine above the normal machine noise.

Keep it simple... mount the VFD directly to the interior metal body, consider adding venting to the upper access plate. VFD fans can be typically set to run all the time, only when the VFD is in a run mode or based on thermal temperature.

 

[m1kemex]

I have an ABB that sounds like it's going to take off. As long as it's not completely air-tight, I doubt it'll fry itself.

 

[Dabbler]

@Rata222 You might consider this: every BP style mill I've rebuilt has had chips in the column. The normal thought is "HOW????" but it seems to happen. At the very least you need a shroud above the electronics in case. (belt and suspenders)

The built in fan will be more than adequate for cooling the board in the presence of the secondary cooling effect of the column and base. Even when using large cutters, a milling machine puts a very light load on the VFD (electrically speaking).

I've done 6 VFD installs on both mills and lathes, and consulted on a dozen more, FWIW

 

[Rata222]

Hey guys, the machine will not run production, it's just a small hobby machine. At 72 years old, I won't be standing out there for hours running it. I felt the vfd might be an improvement over continually changing the belts. But more of a reason, is that I just wanted the experience/ satisfaction of doing it- and learning. I will go ahead and install the vfd inside the column without a fan. I have a digital thermometer with a remote sensor bulb that I can put in there and monitor the Heat, to see what is going on with the panel shut. If it looks like it's getting hot I'll adjust the setup. I like the idea of vibration mounts

 

[Rata222]

Thank you guys, all your input is greatly appreciated! The Mill will not run production, it's just a small hobby machine. At 72 years old, I won't be standing out there for hours running it. I felt the vfd might be an improvement over continually changing the belts. But more of a reason, is that I just wanted the experience/ satisfaction of doing it- and learning.
I will go ahead and install the vfd inside the column without a fan. I have a digital thermometer with a remote sensor bulb that I can put in there and monitor the Heat, to see what is going on when the panel is shut. If it looks like it's getting hot I'll adjust the setup.
The vfd arrived today. The unit has a plastic panel in the back, covering the heat sinks. It can be easily removed , but there would still be no metal to metal contact between the recessed heat sinks and the mill body. I like the idea of adding the vibration isolators, and this may actually help air flow to the back of the. We'll see.
One more quick question has anyone seen write ups how I could use the digital output of the vfd, or a hall effect sensor, and connect it to an Arduino??. Punch in my tool diameter and read the speed in sfm on a screen. Or am I asking too much? It just sounded interesting.

 

[Dabbler]

One more quick question has anyone seen write ups how I could use the digital output of the vfd, or a hall effect sensor, and connect it to an Arduino??. Punch in my tool diameter and read the speed in sfm on a screen. Or am I asking too much? It just sounded interesting.

For 94 I bought a digital tach/hall effect sensor/magnet 2 years ago on *bay... works fine. Even at twice the price, no need for Arduino.

NOW FOR THE GOOD NEWS.

All VFDs have a multiplier, so if you leave your pulleys alone, you can change the display from frequency to RPM directly. That is, if you have thedetachable type VFD display/control panel.

 

[mksj]

Two things to consider.
First, if the VFD has an open back and is not mounted against a flat surface the airflow over the heat sink is compromised as well as loosing the heat dissipation from direct contact to a metal surface. If you want to to isolate it, mounted it to an aluminum plate and then do what you wish to insulate that plate from the machine, but really a wasted effort.

Regarding the speed output, almost all VFD's have an analogue output that is a 0-10V and can be programed for the Hz/Speed (as well as other adjustments), you just need a 0-10V scalable meter and you can scale it to read RPM. In addition some RPM/Volt meters have additional inputs functions, so they can be scaled for different drive ratios. My mill uses a back gear switch and I often include this in my VFD system builds. You can also use some resisters or trim pots to act as a voltage divider for each pulley ratio and then just use a switch to change the range/voltage output to the analog meter.



There are RPM meters that will also give you SFM, MachTach is open source if you want to build your own or one can buy the Tachulator. I use to install the MachTachs, and when he stopped making them I switched Tachulators. You can hookup either to an optical or hall sensor. You will need a 12VDC power source, which also can be used for LED lighting if you choose. Youri's TuochDRO also has a tachometer input I do not know if it computes SFM and also has a tool library. I rarely use SFM on the mill, mostly use it on the lathe with larger diameter turning. On the mill there are a few simple formulas for SFM and I tend to do most of my milling with fixed diameter endmills 3 or 4 flute and one can make a cheat sheet, but in many cases if using carbide, you will not have the RPM or rigidity to reach the chip load based on the SFM.

 

[Rata222]

For 94 I bought a digital tach/hall effect sensor/magnet 2 years ago on *bay... works fine. Even at twice the price, no need for Arduino.

NOW FOR THE GOOD NEWS.

All VFDs have a multiplier, so if you leave your pulleys alone, you can change the display from frequency to RPM directly. That is, if you have thedetachable type VFD display/control panel.

I don't know if I will be able to leave the pulleys alone yet. Since I haven't run it yet. I received the VFD today . This was just something to think about for the future. But I really appreciate the input. My unit does have the removable panel. I had assumed it would come with a cable but it didn't. So I ordered one today. At this point the hall effect sensor seems a lot easier. But I haven't gotten into the programming yet. But I will.

 

[Rata222]

Two things to consider.
First, if the VFD is not mounted satanist a flat surface the airflow over the heat sink is compromised as well as loosing the heat dissipation from direct contact to a metal surface. If you want to to isolate it, mounted it to an aluminum plate and then do what you wish to insulate that plate from the machine, but really a wasted effort.

Regarding the speed output, almost all VFD's have an analogue output that is a 0-10V and can be programed for the Hz/Speed (as well as other adjustments), you just need a 0-10V scalable meter and you can scale it to read RPM. In addition some RPM/Volt meters have additional inputs functions, so they can be scaled for different drive ratios. My mill uses a back gear switch and I often include this in my VFD system builds. You can also use some resisters or trim pots to act as a voltage divider for each pulley ratio and then just use a switch to change the range/voltage output to the analog meter.

View attachment 502008

There are RPM meters that will also give you SFM, MachTach is open source if you want to build your own or one can buy the Tachulator. I use to install the MachTachs, and when he stopped making them I switched Tachulators. You can hookup either to an optical or hall sensor. You will need a 12VDC power source, which also can be used for LED lighting if you choose. Youri's TuochDRO also has a tachometer input I do not know if it computes SFM and also has a tool library. I rarely use SFM on the mill, mostly use it on the lathe with larger diameter turning. On the mill there are a few simple formulas for SFM and I tend to do most of my milling with fixed diameter endmills 3 or 4 flute and one can make a cheat sheet, but in many cases if using carbide, you will not have the RPM or rigidity to reach the chip load based on the SFM.

View attachment 502009

I had to assume that others have thought of this. But in my searches I didn't turn anything up. I will look at that Tachulator. I have read over your post several times. I'm slowly digesting it. Will continue. Thanks for the tip on no spacing between the vfd and the mounting plate. Since the unit had a plastic panel in the back, I didn't think conduction would play a big role in keeping it cool. But I will take your word for it. You guys all have experience that I don't. Thanks for your continued help.

 

[woodchucker]

All VFDs have a multiplier, so if you leave your pulleys alone, you can change the display from frequency to RPM directly. That is, if you have thedetachable type VFD display/control panel.

really, I didn't know that. I'll have to look for that option. Never saw it.