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Busy Bee CX603 VFD?

canuck750

Active Member
Premium Member
I have a small knee mill that looks just like a Busy Bee CX603, belt driven, single phase, 1hp, 110v motor. The mill is fitted with a DRO on X,Y and Z axis. There is no tachometer.

I would like to have a variable speed drive without moving the belts around and be able to reverse the motor by means of a simple switch.

I have watched a couple YouTube videos showing various small mills converted to 3 phase motors with a VFD, most seem to use a 220v - 3 phase motor, either of 1 hp or 2 hp, and a simple tachometer added with a magnet type pickup reading from one of the belt pulleys. Challenges appear to be programming the VFD.

Being of very limited electric knowledge has anyone completed a complete installation on one of these mills and do you have a list of components used and advice for a novice?

Is it necessary or advantageous to use a 3 phase motor?
Do I need to fit a 220v motor?
Is there a reason to install a 2hp motor over a 1 hp?
Several videos indicate the new setup causes the DRO to malfunction, any thoughts on this?

Thanks in advance for any help!
 
I have a small knee mill that looks just like a Busy Bee CX603, belt driven, single phase, 1hp, 110v motor. The mill is fitted with a DRO on X,Y and Z axis. There is no tachometer.

I would like to have a variable speed drive without moving the belts around and be able to reverse the motor by means of a simple switch.

I have watched a couple YouTube videos showing various small mills converted to 3 phase motors with a VFD, most seem to use a 220v - 3 phase motor, either of 1 hp or 2 hp, and a simple tachometer added with a magnet type pickup reading from one of the belt pulleys. Challenges appear to be programming the VFD.

Being of very limited electric knowledge has anyone completed a complete installation on one of these mills and do you have a list of components used and advice for a novice?

Is it necessary or advantageous to use a 3 phase motor?
Do I need to fit a 220v motor?
Is there a reason to install a 2hp motor over a 1 hp?
Several videos indicate the new setup causes the DRO to malfunction, any thoughts on this?

Thanks in advance for any help!
Yes you need a 3 phase motor and VFD. 220v 3 phase tend to be lowest cost option. Two HP can throw wider face mills, or just use the tool time adage, More power

The programming is easy if you buy a teco westinghouse or other well documented VFD.

The tach is as simple as you say, but use array of magnets for greater accuracy at low speeds.
 
I have converted two mills from the original single phase to VFD driven 3-phase. I echo the comments above. Not sure how difficult it would be for you to get 240V from your circuit breaker box?

There are other advantages beyond the variable speed; smoother, fast braking, reversable and the motor is typically more reliable. After using both I would not hesitate for a second to do the conversion. I would choose a VFD with external brake resistor and sensorless vector control, this is a common feature on anything but the cheapest VFD. You will likely find a 1.5HP motor adequate, but a 2HP will offer more low speed power when turning a large diameter tool at slow speeds.

Your comment about the DRO is interesting. I have had no issues with my DROs. That being said the good DROs use differential signalling that have good noise immunity and the okay DROs use single ended quadrature encoding that is not quite as good and the really lousy DROs use a variety of serial protocols some with no error correction that are just a mistake waiting to happen when there is even a hint of noise. I have used DROs that use both differential and single ended with VFDs and they work flawlessly.

Do be aware that VFDs do radiate EMI that could effect any electronics that is susceptible to electrical noise, however if you:
1) Keep the cable between the VFD and motor short
2) Make sure your VFD, motor and electronics are all well grounded

It's really unlikely you will have a problem.

Beyond access to 240V (a 15 or 20A circuit is suitable), you will need a $5 pot for speed control, a toggle switch for forward/reverse, a couple of pushbuttons, one for start and one for stop and an E-Stop for emergency stops. If you use the external brake for really quick spin downs you will need a 100W resistor about $10 or so.

Your probably going to hear "make sure you get a VFD rated motor" I would ignore that and get whatever motor you can for the lowest cost. I have used very old non VFD motors and they barely get warm even when used at slows speeds. For larger motors or continuous production type settings the VFD rated motors might make sense.

I think we have similar mills.
1734789967177.jpeg
1734789967177.jpeg
 
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Alas if only cheap 3-phase motors were ever available on the island.
 
I have converted two mills from the original single phase to VFD driven 3-phase. I echo the comments above. Not sure how difficult it would be for you to get 240V from your circuit breaker box?

There are other advantages beyond the variable speed; smoother, fast braking, reversable and the motor is typically more reliable. After using both I would not hesitate for a second to do the conversion. I would choose a VFD with external brake resistor and sensorless vector control, this is a common feature on anything but the cheapest VFD. You will likely find a 1.5HP motor adequate, but a 2HP will offer more low speed power when turning a large diameter tool at slow speeds.

Your comment about the DRO is interesting. I have had no issues with my DROs. That being said the good DROs use differential signalling that have good noise immunity and the okay DROs use single ended quadrature encoding that is not quite as good and the really lousy DROs use a variety of serial protocols some with no error correction that are just a mistake waiting to happen when there is even a hint of noise. I have used DROs that use both differential and single ended with VFDs and they work flawlessly.

Do be aware that VFDs do radiate EMI that could effect any electronics that is susceptible to electrical noise, however if you:
1) Keep the cable between the VFD and motor short
2) Make sure your VFD, motor and electronics are all well grounded

It's really unlikely you will have a problem.

Beyond access to 240V (a 15 or 20A circuit is suitable), you will need a $5 pot for speed control, a toggle switch for forward/reverse, a couple of pushbuttons, one for start and one for stop and an E-Stop for emergency stops. If you use the external brake for really quick spin downs you will need a 100W resistor about $10 or so.

Your probably going to hear "make sure you get a VFD rated motor" I would ignore that and get whatever motor you can for the lowest cost. I have used very old non VFD motors and they barely get warm even when used at slows speeds. For larger motors or continuous production type settings the VFD rated motors might make sense.

I think we have similar mills.
View attachment 56297View attachment 56297
Oh that is a nice looking shop, dramatic lighting and all.
 
My shop is small but I'm just thrilled with the way it works, I keep tweaking it when something can be improved. Electronic section and mechanical section, saws and grinders in an adjacent room, and supplies room also adjacent. In my previous house everything was spread out part in garage, part in basement and part in office did not work well at all.
View attachment 56316
View attachment 56317
I’m so envious of you folks who have electronics knowledge and abilities!
 
I have sent an email to Motors Direct, they have an outlet in Edmonton, I asked for a recommendation for a 3 phase 2 hp to fit my small knee mill and a VFD to go with it.

I am no machinist, I am retired and restore vintage motorcycles, mostly Italian makes, I often need to fabricate parts or repair parts no longer available. The mill and lathe have probably paid for themselves over the years. Being able to reverse the mill and drop the speed down to a very slow rotation would be very handy





 
I heard back from E Motors direct… the 3 phase 2 hp motor is not outrageous but the cost of the VFD??? I hope there are much cheaper but still decent quality VFD options.

Brook Crompton PF4N002-2
Your Price: $333.50 + $33.70 shipping + taxes
Lead Time: we can ship this on December 24th, and it should arrive by December 26th, or you can pickup as early as December 24th
Availability: in stock in Edmonton, AB
Product Link: Brook Crompton PF4N002-2
KB Electronics KBAC-27D BlackYour Price: $626.85 + $31.08 shipping + taxes
Lead Time: we can ship this on December 24th, and it should arrive by December 26th, or you can pickup as early as December 24th
Availability: in stock in Edmonton, AB
Product Link: KB Electronics KBAC-27D Black
 
Comes down to risk/benefit analysis. My RF30 mill now has a second-hand Baldor 2HP 220/3 motor ($150 off Marketplace) and an Amazon SIPUN 2.2kw VFD ($150). Works just fine, but my experience with Amazon electronics gear is about 20% failure rate. So I expect that I might need to replace the VFD at some time in the future but I’m willing to take the risk.

I’m comfortable repairing electronic gear so it’s maybe not as much a risk, just yesterday one of the stepper drivers on my engraver stopped working so i had to pull it apart and find the fried bits and fix them. Depending on the failure mode, my skill set sometimes makes buying dodgy electronics less of a gamble.
 
I heard back from E Motors direct… the 3 phase 2 hp motor is not outrageous but the cost of the VFD??? I hope there are much cheaper but still decent quality VFD options.

Brook Crompton PF4N002-2
Your Price: $333.50 + $33.70 shipping + taxes
Lead Time: we can ship this on December 24th, and it should arrive by December 26th, or you can pickup as early as December 24th
Availability: in stock in Edmonton, AB
Product Link: Brook Crompton PF4N002-2
KB Electronics KBAC-27D BlackYour Price: $626.85 + $31.08 shipping + taxes
Lead Time: we can ship this on December 24th, and it should arrive by December 26th, or you can pickup as early as December 24th
Availability: in stock in Edmonton, AB
Product Link: KB Electronics KBAC-27D Black

They steered you wrong... you can use this one just fine

TECO-Westinghouse L510-202-H1-U​

.. under 400 bucks. I got it for just over 300

 
Teco or Schneider for decent quality vfds. Weg or eaton is a good option as well. Abb or omron if you have the money.
 
eBay is your friend, IIRC I paid about $50 for name brand good ones that were pulled from industry in the rust belt. They have been working like new for years. The only bad VFD I have ever had was a new one from Amazon that died after about 9 months but was actually only used for perhaps a few hours of actual use. Unfortunately either the supply of good used eBay VFD's is shrinking or more people are snapping them up, because I have a search trigger and it does not wake me up to deals very often for quite a while, I guess I need to increase the price range in my alert..

Hmmmm I just did a quick eBay search, really slim pickings and prices are 3-5x what I was paying pre Covid.
 
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I think Hitachi is another good option. They support external resistive braking.

Another thing to look for is support for a remote control panel.
 
I heard back from E Motors direct… the 3 phase 2 hp motor is not outrageous but the cost of the VFD??? I hope there are much cheaper but still decent quality VFD options.

Brook Crompton PF4N002-2
Your Price: $333.50 + $33.70 shipping + taxes
Lead Time: we can ship this on December 24th, and it should arrive by December 26th, or you can pickup as early as December 24th
Availability: in stock in Edmonton, AB
Product Link: Brook Crompton PF4N002-2
KB Electronics KBAC-27D BlackYour Price: $626.85 + $31.08 shipping + taxes
Lead Time: we can ship this on December 24th, and it should arrive by December 26th, or you can pickup as early as December 24th
Availability: in stock in Edmonton, AB
Product Link: KB Electronics KBAC-27D Black
Kijiji and Craigslist have lots of 3ph motors in the $50-100 range.
 
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