[How do I?] VFD recommendations for Maximat lathe/mill

cederholm

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Hi guys,

I have an old Maximat 3 in 1 from the sixties. It's three phase 240v and been running single phase on an old converter since the 80's. I'd like to switch it to a pair of VFDs (on for the lathe and one for the mill). Please see the motor specs (in German) in the attached photo and advise on a budget minded VFD if you could.

Thank you,
Carl290014290015
 
Looks like it takes 3 amp at 220v so even one of the very smallest VFD units would be enough to power it.
I have heard some of the cheapest imported VFDs have reliability issues so I would be inclined to buy from a US dealer , brands such as Teco and Lenze. I would want some kind of warranty.
mark
ps Nice lathe, rare- looks like it has flat ways
 
Thank you Mark, very helpful. Should I be looking for anything specific in regard to specs?

And thanks about the lathe - it does have flat ways.

- Carl



Looks like it takes 3 amp at 220v so even one of the very smallest VFD units would be enough to power it.
I have heard some of the cheapest imported VFDs have reliability issues so I would be inclined to buy from a US dealer , brands such as Teco and Lenze. I would want some kind of warranty.
mark
ps Nice lathe, rare- looks like it has flat ways




Sent from my iPhone using Tapatalk
 
For that motor you will want a VFD good for at least 3 amps. That rules out 1/4hp and 1/2hp VFDs. The Teco L510-101-H1-U is a 1hp drive rated for 4.3 amps (It's 120 V AC single phase input) or the Teco L510-201-H1-U (same 1 hp, 4.3 amp rating but it's 240V AC single phase input). Personally if I already had 240 available I would go that route. (I assume both motors are rated the same, make sure you check that.)

The Teco L510's in that size run about $140 with free shipping.
 
on the other side of the coin,
i have extensively tested (5) brands of (cheap) inexpensive chinese VFD's
out of the 5 units in testing (harsh environment) i have not had a VFD failure
these are being tested on from 1 hp to 5 hp equipped machines for the past 3 years
your results may vary.

i see no reason to spend any more than you have to.


here is a unit i have tested, it would suit your needs for a 3phase lathe or milling machine up to 8 amps @220v
it is a single phase in, 3 phase out unit
 
Yes there was a long period where the cheap VFDs were reported to work fine, then just lately I began to see some complaints of premature failures.
You pay your money and you take your chances I guess
 
Really helpful all - thank you! Any advice on hooking one up? More specifically, identifying the wires that are coming out of the motor. Remember, the motors are hook up and running now if that helps.

And yes Rich, both lathe and mill have the exact same motor.

~ Carl
 
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There have also been a number of individuals that have purchase the HY or generic Chinese VFDs and they have not worked due to limited programming configurations, have been DOA, or were missing components like the braking module needed for an external braking resistor. I have assisted a few individuals that have had these problems, plus a few other problems. The cheap basic VFDs do not have the programming parameters needed for many installations. There are also a lot of individuals that are using these and they have worked, but it is the only VFD that I have consistently have had repeated problems with.

Since the Teco L510 series is not much more, you get a warranty and technical support, it is what I recommend for bare bones VFD at not much more than the HY VFDs. The L510 still lacks the braking circuity for an external braking resistor, so a poor choice for lathes 12" or bigger or larger mills. Teco has the E510 which has more features, but about twice the price. There are a number of VFDs in the mid price range that work very well. The HY type VFDs supposedly can run up to something like 7.5Hp motors with single phase input, but in other forums that I participate in people who have looked inside these units are doubtful that the electrical components are commensurate with the VFD rating. Ok for light duty, but I only had problems with the few I encountered. FYI, someone else who looked into these units found that those HY units with a speed pot on the panel had a braking module built in, those without a speed pot did not.

I would go with CluelessNewB recommendations, since both motors are the same, you could use one VFD and switch the VFD motor inputs from one to the other. The VFD should be stopped when this is done, and alternative is to use a 4 pole 3 way switch motor 1 - OFF - Motor 2, three poles switch the motor inputs, the 4 th pole disconnects the VFD input common in the off position.

There are two common run configurations for VFD known as 2 wire control and 3 wire control. Two wire control uses a sustained switch for Forward -Off - Reverse, the down side of this configuration is that the motor will start on power up if in the run position. Some VFDs have a lockout if this is encountered, and the switch must be cycled through the stop position for the VFD to run. Three wire control uses momentary buttons for run and stop, and a sustained Forward/Reverse switch for direction. Typically I use 3 wire control in the mill, and 2 wire control on a lathe with a power up lockout if the switch is in a run command.
 
Any advice on hooking one up? More specifically, identifying the wires that are coming out of the motor. Remember, the motors are hook up and running now if that helps.


(These instructions use the markings on the Teco L510 VFD, other brands should be similar)

Mark and take pictures of all your wiring before you disconnect anything!

Since this appears to be a single voltage motor you most likely only have 3 wires (plus ground) coming out of the motor itself. These 3 wires will be connected directly to the 3 terminals T1, T2 and T3 on the VFD, there should not be switches of any kind between these terminals and the motor.

Your incoming power will get connected to L1 & L3 For a 120V Model L3 Is connected to the white wire (Neutral) and L1 is connected to the black wire (Line, Hot). For a 240V model L1 & L3 are connected to the two hot lines, it doesn't make any difference which way. You will also want a ground wire connecting the VFD and Motor to the incoming ground.

With just those connections you should be able to run the motor using the front panel of the VFD for testing. There are a few internal parameters that you will want to set to match your motor. There are a bunch more that you won't care about!

If the motor runs the wrong direction swap any two of the motor wires connected to T1, T2, T3.

Any switches used to control start, stop and direction will be connected to the low voltage inputs of the VFD (Common, S1 - S5). If you want to use an external speed control (potentiometer) that will connect to terminals 10V, AGI, AGND. There are lots of options for external control, you can probably use the existing controls if that is what you want. This will also require some programming of a few of the internal parameters.

There are some Youtube videos on the Teco L510 that you may find interesting.
 
The Teco L510 sounds like a good option. I don't want to go so cheap that I cause myself problems.

"I would go with CluelessNewB recommendations, since both motors are the same, you could use one VFD and switch the VFD motor inputs from one to the other."

MKSJ, since I often run both motors at the same time, I would think I would need two. I do this when I use the mill so I can auto feed the part.

Thanks again guys,
Carl
 
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