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[4]

PM-949TS VFD Full Build Control System with Auto Reverse and Back Gear Sensors

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mksj

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Jun 12, 2014
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#1
Normally I do not like to do full VFD build systems, they take way too much time and cost. But I was asked to do two full system builds one for a PM-949TS mill and an second for PM-1440GT lathe. I kinda of caved, figuring I hadn't done builds for either machine and I wanted to see what I could be be built for both. This is the a review of the PM-949TS mill build. First there was the wish list which grew over time, I started out with thinking I would build a basic control board build and then the auto reverse for threading would be nice, and also a back gear sensor to reverse the VFD inputs when engaged. I decided to build the full system as a plug and play because there were just too many variables in the build process that needed to be addressed. The other major challenge that was also requested by another PM-949TS owner was developing a low profile spindle tach system, and I decided to also included a LED Halo light built into the tach sendor ring.

The Tach/Halo LED light needed to be have a very low profile magnetic NPN pickup, the one I chose is only and 1/8 thick by 0.30" wide. I turned a light ring assembly out of 4.25" aluminum stock, which slides up on the ram and extends below the ram about 1/4". The NPN pickup sensor is fitted between this 1/4" and all the wiring brought out through the back of the ring. A small set screw holds the rings in place. I normally embed the a neodymium magnet into the aluminum spindle ring, but it did not work in this case. This NPN sensor has a very short sense range (like 0.050" or less), so I embedded the magnet on the outside of the ring with a very narrow gap between it and the sensor. I milled an outer ridge so the Halo LED snaps on, but also attached it with some silicone sealant to prevent oil contamination. Some pics as follows:

20171127_150126.jpg 20171127_152247.jpg

Spindle Halo light and Tach assembly..jpg
20171214_100915.jpg

The mill control system was a new ground up design as it was a total build, I did use some of the design and features that I incorporated into my knee mill. I use proximity sensors to detect the back gear, so forward is always forward, and a second proximity sensor which triggers an auto reverse for threading. On my mill this is triggered by the spindle stop adjustment ring, I also have an auto start function. In this build we decided to put the following controls in a knee mounted pod, stop, run, forward/reverse, auto reverse, and coolant (with indicator lights for each function). The E-Stop, tachometer and speed control are mounted in a enclosure mounted to the mill head. I used a precision 3 tun speed pot which gives very fine motor control which is set to operate from 20-120 Hz on the 4 pole motor wiring. I used heavy diecast aluminum enclosures, and also polished the unpainted mill head enclosure face. The main VFD enclosure, I decided to go with a larger 20x12x8 NEMA 4X/12 cabinet, so I would not need any vents or fans. It also includes a main power disconnect, VFD fusing, breaker for a dual gang 120V box, brake resistor, 120W 24VDC power supply with 12VDC step-down converter and control system. Everything fit nicely, although a lot of wiring. When completed it ended up working as designed, which made me happy. It was a 3 week build, plus development and sourcing parts. Needless to say I will not be building another one of these systems.

Building the VFD/system control board.
20171204_143511.jpg 20171212_161257.jpg

Mounting the electrical box and 120VAC sockets
949TS VFD  Cabinet External.jpg

Control Pods (including the smaller one which is for the 1440GT)
949 TS and 1440GT control Pods.jpg
Wiring Pods.jpg
20171211_235002.jpg

Programming the VFD and bench testing. The two proximity sensors are the small squares attached to the cables. All the control and motor cables are shielded, and a star ground is used on the back plate.
20171212_160830_001.jpg

Next will be the 1440GT VFD system build, along with a basic VFD conversion for the PM-1440GT which uses the stock control board.
 

Alan H

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Oct 10, 2016
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909
#3
Mark, an interesting and very nice piece of work. You need to open up a panel shop!

Hopefully the lucky recipient of this build will post some photos and videos of it in operation.
 

davidpbest

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Dec 26, 2015
Messages
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335
#4
Wow - Mark, you outdid yourself yet again. That ring light with sensor is really slick. Great job.
 

uncle harry

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Joined
Aug 19, 2013
Messages
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394
#6
Normally I do not like to do full VFD build systems, they take way too much time and cost. But I was asked to do two full system builds one for a PM-949TS mill and an second for PM-1440GT lathe. I kinda of caved, figuring I hadn't done builds for either machine and I wanted to see what I could be be built for both. This is the a review of the PM-949TS mill build. First there was the wish list which grew over time, I started out with thinking I would build a basic control board build and then the auto reverse for threading would be nice, and also a back gear sensor to reverse the VFD inputs when engaged. I decided to build the full system as a plug and play because there were just too many variables in the build process that needed to be addressed. The other major challenge that was also requested by another PM-949TS owner was developing a low profile spindle tach system, and I decided to also included a LED Halo light built into the tach sendor ring.

The Tach/Halo LED light needed to be have a very low profile magnetic NPN pickup, the one I chose is only and 1/8 thick by 0.30" wide. I turned a light ring assembly out of 4.25" aluminum stock, which slides up on the ram and extends below the ram about 1/4". The NPN pickup sensor is fitted between this 1/4" and all the wiring brought out through the back of the ring. A small set screw holds the rings in place. I normally embed the a neodymium magnet into the aluminum spindle ring, but it did not work in this case. This NPN sensor has a very short sense range (like 0.050" or less), so I embedded the magnet on the outside of the ring with a very narrow gap between it and the sensor. I milled an outer ridge so the Halo LED snaps on, but also attached it with some silicone sealant to prevent oil contamination. Some pics as follows:

View attachment 249791 View attachment 249792

View attachment 249793
View attachment 249794

The mill control system was a new ground up design as it was a total build, I did use some of the design and features that I incorporated into my knee mill. I use proximity sensors to detect the back gear, so forward is always forward, and a second proximity sensor which triggers an auto reverse for threading. On my mill this is triggered by the spindle stop adjustment ring, I also have an auto start function. In this build we decided to put the following controls in a knee mounted pod, stop, run, forward/reverse, auto reverse, and coolant (with indicator lights for each function). The E-Stop, tachometer and speed control are mounted in a enclosure mounted to the mill head. I used a precision 3 tun speed pot which gives very fine motor control which is set to operate from 20-120 Hz on the 4 pole motor wiring. I used heavy diecast aluminum enclosures, and also polished the unpainted mill head enclosure face. The main VFD enclosure, I decided to go with a larger 20x12x8 NEMA 4X/12 cabinet, so I would not need any vents or fans. It also includes a main power disconnect, VFD fusing, breaker for a dual gang 120V box, brake resistor, 120W 24VDC power supply with 12VDC step-down converter and control system. Everything fit nicely, although a lot of wiring. When completed it ended up working as designed, which made me happy. It was a 3 week build, plus development and sourcing parts. Needless to say I will not be building another one of these systems.

Building the VFD/system control board.
View attachment 249795 View attachment 249804

Mounting the electrical box and 120VAC sockets
View attachment 249803

Control Pods (including the smaller one which is for the 1440GT)
View attachment 249799
View attachment 249800
View attachment 249801

Programming the VFD and bench testing. The two proximity sensors are the small squares attached to the cables. All the control and motor cables are shielded, and a star ground is used on the back plate.
View attachment 249802

Next will be the 1440GT VFD system build, along with a basic VFD conversion for the PM-1440GT which uses the stock control board.

WOW .....super build.
 

Ramblerman68

MT-3 Duct Taper
Registered Member
Joined
Dec 27, 2016
Messages
4
Likes
7
#7
Oh sure Mark, now that I've decided to get the same mill, you aren't gonna build any more?!! Hahaha. Awesome work as always sir
 

Kamloopsendo

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Joined
Dec 31, 2016
Messages
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28
#8
Normally I do not like to do full VFD build systems, they take way too much time and cost. But I was asked to do two full system builds one for a PM-949TS mill and an second for PM-1440GT lathe. I kinda of caved, figuring I hadn't done builds for either machine and I wanted to see what I could be be built for both. This is the a review of the PM-949TS mill build. First there was the wish list which grew over time, I started out with thinking I would build a basic control board build and then the auto reverse for threading would be nice, and also a back gear sensor to reverse the VFD inputs when engaged. I decided to build the full system as a plug and play because there were just too many variables in the build process that needed to be addressed. The other major challenge that was also requested by another PM-949TS owner was developing a low profile spindle tach system, and I decided to also included a LED Halo light built into the tach sendor ring.

The Tach/Halo LED light needed to be have a very low profile magnetic NPN pickup, the one I chose is only and 1/8 thick by 0.30" wide. I turned a light ring assembly out of 4.25" aluminum stock, which slides up on the ram and extends below the ram about 1/4". The NPN pickup sensor is fitted between this 1/4" and all the wiring brought out through the back of the ring. A small set screw holds the rings in place. I normally embed the a neodymium magnet into the aluminum spindle ring, but it did not work in this case. This NPN sensor has a very short sense range (like 0.050" or less), so I embedded the magnet on the outside of the ring with a very narrow gap between it and the sensor. I milled an outer ridge so the Halo LED snaps on, but also attached it with some silicone sealant to prevent oil contamination. Some pics as follows:

View attachment 249791 View attachment 249792

View attachment 249793
View attachment 249794

The mill control system was a new ground up design as it was a total build, I did use some of the design and features that I incorporated into my knee mill. I use proximity sensors to detect the back gear, so forward is always forward, and a second proximity sensor which triggers an auto reverse for threading. On my mill this is triggered by the spindle stop adjustment ring, I also have an auto start function. In this build we decided to put the following controls in a knee mounted pod, stop, run, forward/reverse, auto reverse, and coolant (with indicator lights for each function). The E-Stop, tachometer and speed control are mounted in a enclosure mounted to the mill head. I used a precision 3 tun speed pot which gives very fine motor control which is set to operate from 20-120 Hz on the 4 pole motor wiring. I used heavy diecast aluminum enclosures, and also polished the unpainted mill head enclosure face. The main VFD enclosure, I decided to go with a larger 20x12x8 NEMA 4X/12 cabinet, so I would not need any vents or fans. It also includes a main power disconnect, VFD fusing, breaker for a dual gang 120V box, brake resistor, 120W 24VDC power supply with 12VDC step-down converter and control system. Everything fit nicely, although a lot of wiring. When completed it ended up working as designed, which made me happy. It was a 3 week build, plus development and sourcing parts. Needless to say I will not be building another one of these systems.

Building the VFD/system control board.
View attachment 249795 View attachment 249804

Mounting the electrical box and 120VAC sockets
View attachment 249803

Control Pods (including the smaller one which is for the 1440GT)
View attachment 249799
View attachment 249800
View attachment 249801

Programming the VFD and bench testing. The two proximity sensors are the small squares attached to the cables. All the control and motor cables are shielded, and a star ground is used on the back plate.
View attachment 249802

Next will be the 1440GT VFD system build, along with a basic VFD conversion for the PM-1440GT which uses the stock control board.
Chevy mentioned that you had built his tach and light ring so Iwent looking for this thread. VERY nice work once again.
Alex
 

mksj

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#10
Thanks Alex and David, I think David has me beat by a mile when it comes to meticulous work. The challenge on installing a tach on machines with a back gear is that the speed sensor needs to be attached to the spindle in order to get the correct RPM. Factory VFD systems with RPM tachs take the VFD analogue output (0-10V) and use a scalable voltmeter to display a calculated RPM, and use a back gear sensor to change the scaling range.
 
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