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gr8life
02-02-2010, 12:43 AM
In the process of replacing the rice grinder motor in my 4003G. Has anyone done a variable speed replacement on this lathe? If you have I would really like to hear from you before I plunk down my hard $$$$$$$$$$.
thanks
ed

Richard-TX
02-02-2010, 12:56 AM
In the process of replacing the motor in my 4003G.

If you put a 3 phase motor on it and basic VFD like a Teco FM50 you will be very very happy. I put a 2hp FM50 on mine and it fit in the electrical cabinet.

It isn't difficult to do, just time consuming. Adding the VFD and 3 phase motor to my 4003 has transformed it into a smoother, quieter, and easier to use lathe.

Remember to order a new motor pulley. The original motor pulley has a metric bore. Pulleys are available from Surplus Center and they are quite good.

Here is a picture of my front panel after the VFD install. I replaced two of the pushbuttons. The original stop button was a PITA.

http://rich.homeunix.com:443/metal-lathe/pics/HPIM1966-r.jpg

Bguns
02-02-2010, 12:57 AM
Helped Hwingo do a PM1236.

I have a 4003.. Non G ...

What do you want to know?

The American motor frame (145T) was almost a direct bolt in on the PM and looks almost identical to 4003 ...

The Shaft diameter is smaller on US motors so a new double vee pulley (~ 2.75 pitch) will be needed.

Grizzly has US made pulleys too...

gr8life
02-02-2010, 01:10 AM
Thanks for the quick replies. I am looking at a WEG metric motor w/ a 90 frame that should mount directly and the shaft should take the original pully. I hope. Were you able to keep any of the original control buttons? Any wiring help would be appreciated.
thanks
ed

gr8life
02-02-2010, 01:13 AM
Also where did you put the VFD and speed control?
ed

Richard-TX
02-02-2010, 01:19 AM
One more thing. Don't even try to figure out the wiring of the existing contactors. All you need is one contactor for the main power. The rest will be surplus/spares.

What I did was to disconnect the wires connected to the bottom terminal strip and pulled the sub panel. I think it is a lot easier to work on that way.

Richard-TX
02-02-2010, 01:26 AM
The speed pot replaced the indicator lamp. I replaced the main power button and start button with illuminated buttons. I want to dress the wiring in my 4003 electrical cabinet and when I do I will take some pictures.

Wiring? You need a good continuity tester for that. The existing FWD-OFF-REV switch near the carriage is a little odd, but it works with almost any VFD that accepts a contact closure.

In addition to dressing up my cabinet wiring, I was also planning to make a proper wiring diagram. I will post it when I do. It may prove useful to you.

Black_Moons
02-02-2010, 01:28 AM
You can save the existing controls, but you'll likey have to add some more.
VFD is really the way to go. I have been looking at the same upgrade for my lathe and pertty much settled on a teco N3 due to its slightly more advanced features then the EV.. http://www.tools4cheap.net/products.php?cat=46 has a list of them with prices and manuals.

Also look into getting a cheap (<$100) resistor bank for the braking resistor. Some VFD's require uberexpensive braking 'modules' that cost more then the VFD.
the N3 does not, just needs a resistor, Not sure about the EV, it doesnt really clarify it in the manual.
This bank will let you stop the motor on a dime (for threading) WITHOUT heating up the motor like DC injection, and stop much faster then DC injection.

gr8life
02-02-2010, 02:06 AM
I must be dumb but how does the breaking work? Do you hit a button or flip a switch?
ed

Bguns
02-02-2010, 02:21 AM
Simply the VFD injects DC into motor. There are a couple ways to do it though. One dumps motor (now acting as generator) output into resistors.

The stop on a dime feature is hardly needed, when you can crank spindle speed down to 2 rpm...

And in low gear the gear reduction slows it down pretty quick anyway...

Black_Moons
02-02-2010, 02:39 AM
Braking is usally setup to just stop the lathe when you turn it off :P
(as the 'turn off motor' control now just controls the VFD, do NOT insert a switch beween the VFD and motor unless you want to fry the VFD)
Note: you'll also need a new 3 phase motor for your lathe to go with the VFD.

bguns: some people like to get threads done in less then an hour.

lakeside53
02-02-2010, 02:41 AM
With just braking resistors, you can't stop "on a dime" (unless you are thinking 2-3 seconds at low loads/medium speeds, and a lot more at high loads/speed). As the rpm falls so does the braking efficiency. For "snappier braking", combined with the braking resistors, you apply DC injection at the last part of the deceleration cycle to positively stop the motor. The DC injection will stop the motor "dead" and in fact lock it (keep that time short...). A thermistor mounted inside the motor and wired to the VFD will protect the motor from inadvertant overheating, but I doubt you'll have any problems in a home shop.

The problem with most low end VFDs is that they only allow a specified time or % of full rpm for the start of DC injection. It's trickier than it looks to find a balance between high rpm heavy loads and low rpm.

I assume you know this, but ... you still need your gears/pulleys. Yes... a vfd allows variable speeds, but does not provide full torque and HP except close to the normal motor speed. For example.. if you ran your motor is say 1750 rpm/60hz and the spindle a 1750 rpm, and just used the variable speed control to take it back to 80rpm for threading, it would have little to no torque or HP. Similar problems occur as you increase the max frequency. I run mine up to 120hz (2X normal speed) and I can definitely notice the HP loss at the top end.

Ditch the motor fan and put an electric fan in its place. The original fan provide little cooling at lower rpm. A surplus computer fan works fine and can be controled from the vfd relay.

Select a decent VFD, then just play with it. That's how you'll learn... Luckily, its pretty hard to damage so long as it's directly connected to the motor - i.e no switches or contactors between the VFD and the motor.

Richard-TX
02-02-2010, 02:43 AM
You can save the existing controls, but you'll likey have to add some more.


Actually he will only have to replace the indicator lamp for a speed pot assuming that he wants a speed pot on the lathe's front control panel.

The pushbutton stop and start switches control the main power contactor so that remains unchanged. The jog/inching button also remains unchanged. The fwd-off-rev handle-switch also remains unchanged.

You are correct about the braking resistor. It will make a big difference. All of the Teco drives can accept a braking resistor and it is cheap too.

As far as the N3 goes, it is a newer, more expensive, and in some ways, a less capable version of the Teco 7300cv. If I recall correctly, there is an issue with physical size. I don't think the N3 or 7300 will fit in the 4003 electrical cabinet. I could be wrong. If either does fit, he will need some forced cooling for sure. I put a fan on mine. I like to keep things cool.

The Teco 2 hp FM50 is $145 from factorymation
http://www.factorymation.com/s.nl/it.A/id.196/.f

The Teco 2 hp 7300cv is $240 also from factorymation.
http://www.factorymation.com/s.nl/it.A/id.5577/.f

The 2hp N3 is $259.99 from tools4cheap.

The 2hp braking resistor is $20.00 from factorymation.
http://www.factorymation.com/s.nl/it.A/id.809/.f?sc=2&category=15647

There is also another drive that may fit and feature wise, it sits nicely between the FM50 and 7300/N3 and that is the EV.

A Teco 2hp EV drive is $177 and is available from dealerselectric.
http://dealerselectric.com/item.asp?PID=394

The FM50 is a v/hz drive
The others are a sensorless vector capable drive. (more torque below 20 hz)

I feel that I must caution you on running your 4003/4002 lathe at very low RPM for an extended period of time. The 4003/4002 headstock is a splash lubrication system. Spin the motor too slow and no oil gets thrown up. As a result the spindle bearings and other gears will get little to no oil.

When I thought about this issue I decided that the FM50 was more than sufficient for my needs. Very rarely will I run the motor below 20 hz and when I do it is for just a few seconds at a time. I have yet to run out of torque with the FM50 on my 4003.

Richard-TX
02-02-2010, 02:46 AM
I must be dumb but how does the braking work? Do you hit a button or flip a switch?



The braking is automatic and adjustable. Once set, you forget it. The VFD just does it.

lakeside53
02-02-2010, 02:54 AM
I feel that I must caution you on running your 4003/4002 lathe at very low RPM for an extended period of time. The 4003/4002 headstock is a splash lubrication system. Spin the motor too slow and no oil gets thrown up. As a result the spindle bearings and other gears will get little to no oil.

.


Yes.. I have a similar problem on my big lathe - it has a oil pump that pipes filtered oil to the important (expensive..) bearings. I need to add a separate or auxilialry pump if I'm to run at other than 60hz (project #874!)

On my smaller lathe, the big headstock gears actually lift the oil and spread it at any speed, so I have less concerns.

But just "splash".. yep... care...

Bguns
02-02-2010, 03:03 AM
I should have said, crank down to 2 rpm at very end of thread, or near shoulder.

On my Mill, with similar gearing and Hp, I have yet to stall a tool in cut/trip VFD, running spindle speed down in backgear...

I still do not have VFD on Lathe... Mill was first priority... (needed motor anyway)

The lathe has paid for itself just threading barrels, and I am not gray haired yet...

As to oiling .. Pull lid and start at lowest VFD speed. If you get wet, don't worry about splash oiling...

If you are dry :) run VFD up to where oil slings up to where lid would be.

Use that speed as minimum for continuous duty work...

Do not run for extended time at ultra low speed. A simple higher speed run for a second or 2 every 10 minutes should be enough for spindle bearings...

Practical minimum is around 10 hz as Lakeside said. Most motors barely spin at 3 hz and at 10hz there is at least some air flowing from motor fan...

lakeside53
02-02-2010, 03:08 AM
If you have the tool engaged, that will almost always stall the motor and trip the VFD... unless it's a very fine cut. A practical cut off is about 10 hz anyhow.

hwingo
02-02-2010, 10:34 AM
If you have the tool engaged, that will almost always stall the motor and trip the VFD... unless it's a very fine cut. A practical cut off is about 10 hz anyhow.

As Bguns stated, he installed the new 3 ph motor and VFD on my lathe. Just to see how the "system" worked, I made a .125" cut in aluminum at 10 Hz using low gear (spindle turned VERY, VERY slowly) and never once did the lathe struggle. Naturally, I have NEVER had a need to "hog metal" but this was a pleasant surprise when the VFD did not "trip".

Harold

lakeside53
02-02-2010, 01:05 PM
Sure.. in a low gear you are getting mechanical advantage. Try that in 1:1 motor -spindle gearing - at 10hz, a 60hz motor has less than 15% of its HP and torque - approximately.. and many variables included torque boosting available from some vfd's. At 2hz (if the motor can run that low) - almost nothing.

If you are]consuming hp in excess of what a motor could deliver at lower rpm, flipping speed down very low during turning to end a cut near a shoulder will show this effect markedly.

CNC lathes often have huge motors to compensate for this. A 20 hp motor on a 16x60 machine is not uncommon. 15% of 20 is a lot more then 15% of 1hp :D

MTNGUN
02-02-2010, 01:35 PM
I can't think of any reason to retain ANY of the lathe's original contactors. I don't use them. Good riddance, since the chinese contactors are notoriously unreliable.

The sensorless vector drives are very torky at low rpms.

I have one process that requires operating the motor at 70 Hz for half the time and at 25 hz the other half. After running that process ALL DAY LONG the motor temperature is barely above ambient.

The Teco EV will run smoothly down to 10 hz, but I have no logical reason to do so.

99.9% of the time I leave the gear selector at a mid-range position and use only the VFD to control speed. A single motor pulley is fine, can't imagine why you would need a double pulley.

By the way, the EV does have a built-in braking resistor. The manual shows terminals for connecting a braking resistor, though there are no specific instructions. The built-in resistor will not "stop on a dime," but it stops about twice as quickly as it would otherwise.

gr8life
02-02-2010, 02:50 PM
I know some people get upset when a thread runs this long, sorry to be so unknowledgeable (read dumb). Ordered an new 3ph motor & VFD this morning. Has anyone put a tachometer on? I put a VFD on my Lagun and have made a chart of Hz=speed but would like to have a tach on the lathe. Any thoughts?
thanks
ed

MTNGUN
02-02-2010, 05:39 PM
One of my lathes has a tach that interfaces with the CNC control. It's nice for the dataholic in me, but most of the time I just go by Hz.

For a manual lathe, it should be easy enough to use a handheld optical tach, shouldn't it ? Or, use a contact tach on a workpiece mounted in the spindle. You'd only have to do it once to establish the relationship between Hz and spindle rpm for each gear.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=66632

3hp is overkill but nonetheless it should work great.

Richard-TX
02-02-2010, 06:20 PM
I know some people get upset when a thread runs this long, sorry to be so unknowledgeable (read dumb). Ordered an new 3ph motor & VFD this morning. Has anyone put a tachometer on? I put a VFD on my Lagun and have made a chart of Hz=speed but would like to have a tach on the lathe. Any thoughts?
thanks
ed

Ed,

You are NOT dumb. Maybe a little ignorant, but we all are to one degree or another. You are also smart enough to know when to ask for help. Actually you seem to be a rational and logical fellow.

Since the headstock is a mechanical gearing system, you have to roll your own so to speak. If you bought the 7300CV then you could program the VFD to read a shaft encoder and display the spindle RPM. Of course you have to install a shaft encoder or detector on your spindle. This is NOT a plug-n-play feature but something that will require some interfacing and programming skills. Other than that, you are left with a chart.

Richard-TX
02-02-2010, 06:32 PM
By the way, the EV does have a built-in braking resistor. ...The manual shows terminals for connecting a braking resistor, though there are no specific instructions. The built-in resistor will not "stop on a dime," but it stops about twice as quickly as it would otherwise.

I think you are referring to a built in braking transistor.

While there are no specific instructions per se, the diagram on page 5 of the full manual shows how to hook up the resistor, aka braking unit. Usually there are additional hookup instructions that come with the resistor.

Finding the full manual for the EV can be a challenge. You can get a copy at the link below.

http://rich.homeunix.com:443/VFD/ev_operating_manual-full.pdf

Richard-TX
02-02-2010, 07:05 PM
I can't think of any reason to retain ANY of the lathe's original contactors. I don't use them. Good riddance, since the chinese contactors are notoriously unreliable.


Whether you reuse an existing contactor or use a different one is entirely up to the you. New IEC contactors suitable for this application are less than $20.00.

I took out the original subpanel and made a new one from scratch. I did not reuse anything that was on the original panel. I wanted to keep the original panel as-is in case I ever sold the lathe and the new owner wanted the original 1 phase motor and the original subpanel reinstalled on it.

There is a good reason to have a contactor for the power coming in. You really want some sort of disconnect for the power if you want to even come close to the latest NEC standards. That is why the stock 4003 has a contactor for the main power.


Below is a conceptual diagram of how my4003 lathe is currently wired. The aux relay contacts are connected to a small 12 volt cabinet fan and supply. The section labeled "motor controls" include the existing controls and a speed pot. Grounds are not shown, however neutral is.

http://rich.homeunix.com:443/presentation/vfd-plus-schematic3.JPG