[twobobbwana]

I bought a Stepperworld FET 4 kit with Sanyo Denki motors (50 oz) a few years back and have recently took the conversion of my RF30 mill more seriously.

The problem is that I've got no response from the Y axis output (tested with motors that work in the X,Z,W outputs on the board).

A further problem is that a couple of the motors will hum, or not, and make no attempt to spin when connected to a proven port.

Autopsy of the failed motors reveal that corrosion is the issue and they have not responded to attempts to rectify this.

I have had no success trying to source identical motors -which by all accounts will be inadequate anyway.

A local techspert replaced the steppermotor "ON/OFF" switch on the board but the situation - with "Y" - is unaltered.

Could this be a pin "allocation" problem with the printer port on the computer ???

With the supplied SYN Electronics SYS2030-8-2 (Input 100-240VAC 47-63 HZ,Output +5 V @ 1.5V, +24V @ 3.0A) what are the largest Nema 23 type steppers that I can use.

It may be that this equipment may end up being inadequate for my intended use but a working system would provide motivation for my cnc conversion.

[twobobbwana]

bump

[109jb]

I had a stepperworld FET 4. My advice would be to forget about it. There are much better drives available that you don't have to mess with matching power resistors for your motors and all that crap. Based on my experience with the FET4, I put it in the circular file a long time ago. In my opinion you would do much better with other drivers. Even the cheapo TB6600 in the link below is a better choice as far as I am concerned. At $20 to get 3 of these, I wouldn't even bother with the FET4. This would be the cheap way to go.

Single Axis TB6600 DC12-45V Two Phase Hybrid Stepper Motor Driver Controller GD | eBay

Having said the above, If you want to get a decent setup for an RF30 size mill, I would just get this.

High-Torque Stepper Motor, Stepper Motor, Driver, Stepper Motor kit, DC Servo Motor, DC Servo Motor kit, Stepper Motor Power Supply, CNC Router, Spindle, and other Components. Stepper Motor | Stepper Motor Driver | CNC Router | Laser Machine | 3D Prin

[twobobbwana]

109jb,

I hear what you're saying.

I'm only persisting with the FET4 as it's what I've got my money sunk into. So I'm trying to make the most of it. It seems I've "bought a turkey" but, at present, I'll stick with the "turkey" I have.

FET 4 is four axis.

If all else fails I'll start again. There are plenty of kits around.

[john-100]

if this is your board is this one

Attachment 341350

I guess its using the now discontinued UCN504 to control the FET's

Attachment 341352

do you have a manual for the board ?

if you don't , it should be easy to trace the connections between the
IC step(11) and direction(14) inputs and the 25 pin printer port connector

Attachment 341354

how are you controling the motor current ???



John

[twobobbwana]

John,

Control of FETs is via a UCN5804B.

I have replaced the "Y" control/switch as I thought it was suspect.

I have the blurb that they sent with the kit. Among it is a diagram of the board but no "manual" that shows what does what.

Motor current control - I am using the powersource (SYN Electronics Model SYS2030-80-2 - Output +5v @ 1.5A , +24V @ 3.0A) supplied with the kit and wired as per instructions.

Many thanks for your interest and assistance John

[john-100]

with high resolution photos of both sides of the board it may be possible to trace enough of the circuit to work out the exact function of the switches and the function of each printer port pins

for each axis you have 3 switches -
2 switches to control the step pattern (IC pins 10 &11) - 1 switch for full or 1/2 step + a second switch for 1 or 2 phase
a 3rd switch controls IC pin 15 which must be grounded to enable that axis

how is the motor current controlled ?
24V motors run off a 24V supply or are they for example 3V motors with resistors dropping the excess 21V ???

John

[109jb]

FET3 and FET4 boards use power resistors to adjust current. So, change motors, and you have to buy new power resistors to match. I remember the instructions for mine had a calculation that you had to do to determine power resistor sizing. When I wanted to switch motors on mine I found that the power reisitors were costly and you could actually buy a chopper drive cheaper than messing with the FET board.

[twobobbwana]

john,

the motors I am currently using are 24V/.18A Uni-Polar and the power supply is 24volt so no resistors are required (?).

109jb,

"The recommended max current drive of these boards is 5 amps per phase". Is what is stated in the paperwork that was included. I'm assuming that it's o.k. to upgrade motors as long as I don't exceed "5 amps per phase"

Yes there is "STEPPERCALC.EXE" mentioned and talk of resistors.

I haven't got that far yet. I'm just trying to get the whole 4 axis working with the piddling .18A (85oz) motors that I got with the kit. My reading indicates that I probably need 425 oz motors but will "burn that bridge when I get there".

[109jb]

john,

the motors I am currently using are 24V/.18A Uni-Polar and the power supply is 24volt so no resistors are required (?).

109jb,

"The recommended max current drive of these boards is 5 amps per phase". Is what is stated in the paperwork that was included. I'm assuming that it's o.k. to upgrade motors as long as I don't exceed "5 amps per phase"

Yes there is "STEPPERCALC.EXE" mentioned and talk of resistors.

I haven't got that far yet. I'm just trying to get the whole 4 axis working with the piddling .18A (85oz) motors that I got with the kit. My reading indicates that I probably need 425 oz motors but will "burn that bridge when I get there".

The voltage rating of the motor is the max voltage that you can apply where the natural current won't exceed the motor's max current rating. If you apply 24V to a 12V motor, the natural current in the coils will exceed the current rating of the motor and it will have to be limited somehow. The FET boards do that by using the power resistors. Other drivers, chop the current to keep it within limits. The chopper drives are easy to set current usually having a simple DIP switch or a potentiometer to set the current. When you change motors you will need to get power resistors.

On voltage, you need to greatly exceed the voltage listed on the side of the motor to achieve good performance. You will have poor performance running motors at their case rated voltage. For example, my motors are rated at 3 V and I run them with a 48 V power supply, and would run them at more if I had drivers that would take more.

For a RF-30, which I believe has about an 8.5" x 30" table, 425 oz-in would be absolute minimum. The RF-30 has a pretty heavy table and those motors would work but feeds would be slow. My G0704 has a Smaller lighter table and I use 570 oz-in motors which are OK, but could be better. I have converted 3 machines so far, a Harbor Freight like a RF-25, the Grizzly G0704, and a more DIY using a XY table and welded steel frame. With my experiences, I would be inclined to use NEMA 34 640 oz-in motors on the X and Y axes, running at least 48V.

[twobobbwana]

109jb,

My schematic of the FET4 board shows dip switches on all axis.

A note says "dip switches 0 0 x Hi Torque
0 1 x Wave Dir
1 0 x Half Step

Not arguing just trying to get my head around this.

I will be ecstatic when I post that everything is up and running but my motors are too small.............how do I fix this ??? Right now I'm struggling to crawl...........we'll worry about speed later.

Yet again thank you for your advice/input..........being totally ignorant of this process I appreciate having the benefit of your knowledge/experience.

My conversion is based on the Chuck Fellows RF30 conversion model. He used 425oz (?) motors and 3 to 1 (later 2:1) gearing.

Mine is based on 3: 1 gearing and has mounts for Nema 23 motors.

[dertsap]

I made the mistake of buying the exact same setup many years ago and I think that your going to be disappointed in it's performance IF it is even possible to get those tiny motors to move your mill .
I had the same determination with using that board and to get more out of it. I eventually bought bigger motors , went thru all the crap of fitting resistors , and after a short period I cut my losses and bought better drivers (gecko) .
Those motors are very weak and they are extremely slow . IF you can move the axis with them then it'll be so slow that the mill won't be of much use anyhow
.
I wish that I could help to get it running , but it's sooooo far gone from my memory on the wiring and such , and I have no more documentation . Best thing I can do at this point is give you the same advice that I refused to listen to and that is to spend the money again and start with a better setup , because it won't be long before you'll find yourself doing it anyhow

[john-100]

Hi twobobbwana

thats correct , no resistors are required when using 24V motors with a 24V supply

what test equipment do you have ?

if you can post the schematic to see how to test the UCN5804 in the event a faulty motor has blown some of the FETs on the Y axis

John



PS

if the FET output stages add to the UCN5804
are any thing like this -


provided the resistors are not too low a resistance they should give the UCN5804 outputs protection from fault currents if the FETs are damaged

[twobobbwana]

John,

A multimeter, driven by someone who can work one, is the available testing equipment.

This process has been plagued with broken fine wires/soldered connections/dodgy stepper motors.

Some of the stepper motors no longer work and I put this down to corrosion. Though I have tried to autopsy them and gently remove any corrosion. Some motors will no longer hum or move. While others are "locked up" and the shaft will not move. I am resigned to replacing some/all motors but wish to "prove" the board first. I still have one working motor to test the board with. The negative press on these boards indicates that I may be "shuffling deck chairs on the Titanic" however I'm hesitant to abandon it...................for the time being.

While I have found circuit diagrams I have been unable to post/link them.

The board is back with the "tech" with more wiring issues................along with your theory on "fried fets".

Supposing a technological miracle and we get this thing going the next issue will be upgrading motors.

The board has the ability to handle 5amps in unipolar motors of 5,6 or 8 wires so I am hoping that a usable motor can be found within those parameters.