Connecting VFD + 3 phase motor on King PDM-30

[RickyD]

Hi Guys,

I am in the process of installing my Brook & Crompton 3 phase 2hp motor and KB KBDA-27D vfd on my King PDM-30 mill.

I was wondering if I should source my 240v (for the VFD) from the PDM-30 CJX2-1810 internal module (see image), or directly from the 240v outlet?

I like the idea of keeping the stop and run button functional on the mill, in case I need to do an emergency stop.

I was also thinking of connecting the 3 phase output of the VFD directly inside the CJX2-1810 module, since it support 3 phases... then into the motor, but I would also have to externally provide power to the 24v power supply since it cannot accept 3 phase input.

Simply not sure about how to connect all the wiring optimally.

Thanks !!

 

[Susquatch]

I was wondering if I should source my 240v (for the VFD) from the PDM-30 CJX2-1810 internal module (see image), or directly from the 240v outlet?

Directly. Nuff said. Don't even think about cutting corners on this.

I like the idea of keeping the stop and run button functional on the mill, in case I need to do an emergency stop.

Sure, you can use these switches as low voltage controls inputs to the VFD. Most likely, the VFD will stop the motor a lot faster than it used to.

I was also thinking of connecting the 3 phase output of the VFD directly inside the CJX2-1810 module, since it support 3 phases...

Knock that one right out of your head too. The VFD learns about your motor and sets its output accordingly. You should not share different motors on the same VFD.

Two motors, two feeds, two VFDs.

 

[Ironman]

If you want to keep the controls on the mill, you can if you use them to control the 24 volt remote terminal on the vfd. Start/stop/reverse are all there to be wired into outboard switches. If you feel you can't do this better get some electrical help. It only needs to be done once and you can learn from this.
I have done this on my mill, all the former 600volt controls are switching 24 vac now.

 

[BaitMaster]

I’m going to have to be a contrarian here, but I’ll explain why. Your cx module thing is simply a contactor.

On machines that have VFD’s that aren’t constantly operated….. I like to switch the power OFF to the VFD.

Now you could just simply unplug the VFD. I like to run the VFD power through the contactor, utilizing the stop and start buttons to control the contactor which feeds power to the drive, then use a separate 3 position (reverse, off, forward) switch and a potentiometer to “control” the VFD.

I do this for a few reasons.

1) lightning. A VFD left plugged in is susceptible to power surges. Whether or not the manufacturer claims this or that, it happens. Lightning will kill your drive faster then a machining hobby will ruin your investment goals.

2) accidental starts by my kids/friends kids. Sometimes a 2 step process is better.

3) drive catches fire while machining…. E stop shuts power to drive.

I’ve seen all of this stuff happen which is why I do what I do. That being said, plugging the drive into the wall and using the switches low voltage is great too.

 

[Susquatch]

I’m going to have to be a contrarian here, but I’ll explain why. Your cx module thing is simply a contactor.

I don't see that approach as contrarian. I think it's just good experience based practice and great advice.

I've never thought of lightning as a potential problem in my shop. It's only been an ongoing problem at the house because I have a 75ft antenna tower for our internet access. Blown routers and entertainment devices are constant casualties despite various lightning protection devices and strategies.

My barn/shop is a metal building about 10 to 15ft lower elevation with 50ft trees (nature's lightning rods) behind it. Power is an underground supply. I doubt lightning would ever be a problem in my shop.

Nonetheless, I power all my machines with 220V extension cords running to wall outlets and I always unplug them when not in use.

I will need to think about additional lightning protection implications. Lightning does weird things. Nothing is really ever safe from it.

 

[skippyelwell]

@BaitMaster , @Susquatch , I've read many times that power should always be going to the VFD
because they don't like being powered down and when switching them on/off you risk damaging the VFD.

I've had a new VFD on my drill press for the past 3 months working perfectly, then I shut the power off at the breaker panel to do some maintenance work.
When I restored power to the VFD I can't get it to work and am having to send it back to AutomationDirect for repairs.
Might just be a coincidence of course.

 

[slow-poke]

I have double pole switches / contactors on the input power to all my VFDs and I switch them off when not in use. I'm not buying the keep them powered all the time idea. My VFDs are used surplus from eBay and they are old and still working like new. I would do as Baitmaster suggested I think that's good advice.

 

[Ironman]

I’m going to have to be a contrarian here, but I’ll explain why. Your cx module thing is simply a contactor.

On machines that have VFD’s that aren’t constantly operated….. I like to switch the power OFF to the VFD.

Now you could just simply unplug the VFD. I like to run the VFD power through the contactor, utilizing the stop and start buttons to control the contactor which feeds power to the drive, then use a separate 3 position (reverse, off, forward) switch and a potentiometer to “control” the VFD.

Switching power off to the VFD when idle and not powering a motor is benign and harmless, and can protect the device from a surge. Of course my vfd on the drill press has been left on for 9 years now, I ignore my advise.
However, switching the vfd output under load will force you to pay the price. Every single vfd (4) I have warns not to do that.

 

[Susquatch]

@BaitMaster , @Susquatch , I've read many times that power should always be going to the VFD
because they don't like being powered down and when switching them on/off you risk damaging the VFD.

I've had a new VFD on my drill press for the past 3 months working perfectly, then I shut the power off at the breaker panel to do some maintenance work.
When I restored power to the VFD I can't get it to work and am having to send it back to AutomationDirect for repairs.
Might just be a coincidence of course.

New one on me Skippy. I've never heard of that. Maybe @BaitMaster has - he does this for a living. I'll have to do some research to understand the mechanism. Might have something to do with powering up a VFD that is always on.

As an aside, I have input filtering. Not to protect the VFD though. It's there to prevent noise from the VFD affecting the supply lines and other devices connected to it. However, it could also work to protect the VFD from supply line startup spikes from elsewhere.

I'll have to look and see what I can find. I'll post anything relevant.

 

[skippyelwell]

Good to know, when it comes back from repairs I'll put a 220v switch in front.

 

[BaitMaster]

Shutting off a VFD when it is not running is completely fine.

Shutting them off under load can damage them.

Turning VFD’s off when not running is how every VFD gets serviced…. Or machinery gets moved…. Or connections get checked…. They have to be able to be shut off when not running.

A VFD is just a rectifier and an “inverter” circuit with a computer controlling the inverter.

If Shutting off the power to any old inverter doesn’t cause problems when not under load, a VFD doesn’t either.

 

[Susquatch]

So @skippyelwell, I have spent a little time looking at online experiences, idiots online, and thinking a bit about possible causes of both mains power up and power down.

Most of the problems I have reviewed were not on systems like the ones we have in our machine shops. But a few were. Nothing I saw on-line spoke to any root cause concerns. However, they did cause me to think beyond my normal thought processes.

Supply line failures are almost always accompanied by a lot of line noise caused by starting up or shutting down entire subdivisions simultaneously. However, they are not likely to damage a VFD unless.... It is not properly grounded, a ground fault exists, ground loops exist, improper connections or wiring exists, equipment grounding is not done properly, switching or disconnects are installed between the VFD and motor, motor grounds are floating, or other large loads are connected to the same circuit. Doing these things correctly is all part of a proper installation.

A plain old input filter can smooth out some of these issues exactly the same way as they reduce noise feedback from the VFD. They basically filter both ways.

In other words, I think that upstream power line failures are not likely to damage your VFD unless its wired incorrectly or gets hit by lightning.

I don't think that plugging in or using an in-line switch alone can damage the VFD unless its wired incorrectly as described above.

 

[Bandit]

Where I used to work had many lightening storms, often would take out control modulals or entire control computers, sometimes pumps. Our VFD’s seemed to be fairly well protected, except the ones at the tail end of the system. We did lose maybe 2 in 20 years, but they had been in use a while before I had started there and old age with numerous power surges and lightning storms contributed to their failure I am sure.
There was a fairly large grounding cable put in around part of the plant, with larger gauge wiring going to it from all the metal hand rails and wiring trays, this seemed to help protect things more. This was done on advise of an electricial engineer and an older electrician with experience in these areas, in hand with some filters and a heavy duty surge device.
Our VFD’s were always turned off if not in use, unless in part of over level pump control systems or a few other backups. Air blower VFD’s were on automatic (computer) air level controls, varying speeds based on air demand. Not in use blowers had VFD’s turned off.
If turning off and on VFD’s was going to damage them, we would have been changing them all the time!!

 

[BaitMaster]

I’ve seen countless….. and I do mean countless….. black an toasty VFD’s after lightning storms. On irrigation and oil wells.

 

[YotaBota]

I’m going to have to be a contrarian here, but I’ll explain why. Your cx module thing is simply a contact

Agree totally, I have a TECO VFD and it has a "power off recovery" setting. When the vfd loses power it holds all it's settings and when the power comes back it carries on as normal.

I also use the contactor for input power to the vfd and turn it off when done for the day.

The start/stop buttons control the contactor and the fwd/off/rev is controlled by the vfd.

The pot controls the spindle speed and the small switch feeds power to the tach.

 

[skippyelwell]

Thanks guys, that clears up a lot for me.

Agree totally, I have a TECO VFD and it has a "power off recovery" setting. When the vfd loses power it holds all it's settings and when the power comes back it carries on as normal.

I also use the contactor for input power to the vfd and turn it off when done for the day.

The start/stop buttons control the contactor and the fwd/off/rev is controlled by the vfd.

The pot controls the spindle speed and the small switch feeds power to the tach.

View attachment 57399

That looks like a home built unit, is it? It is exactly what I need.
Sorry to the OP for cluttering up your thread.

 

[RickyD]

Thanks for all your input guys. Much appreciated !!
Will definitely never shut off the power to VFD when under load !!

I will hookup my VFD to the PDM-30 contactor to get the 240v from there.

I might try to source an I/O control module for my VFD, I believe it was an option.

Thanks again !!

 

[YotaBota]

That looks like a home built unit, is it? It is exactly what I need.

It's the factory panel, I've added the pot, toggle switch and tach.