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Big steppers don't work
« on: March 02, 2007, 01:48:07 PM »
Hi folks

I'm beginning in CNC and started building my machine. I bought a HobbyCNC board, 3-axis. I have a 24 volts 20 amps power supply. My problem is that all small stepper motors work just fine, but all NEMA 17 & 23 just don't work. This getting really frustrating. I spend the last 5 weeks to try to find the answer. I search the internet, HobbyCNC forum and other places. I tried everything!!! Even other software with the same result.

In Mach3, I set the board for the small steppers and they all work. Now I change them for NEMA23 steppers, made the adjustment on the board, tried automatic axis settings in the settings screen and fine tuning the motor. But they just don't turn. I can feel the motors buzzing but that's it.

I believe this sh.. just happens to me ???

Offline Chip

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Re: Big steppers don't work
« Reply #1 on: March 02, 2007, 03:53:22 PM »
Hi, tk421

Post you type of control,

Steppers come in many, many volts/ Amp, Post the Ohm's readings of all your different steppers, and any data that's on them.

This will give us a start, Chip
Re: Big steppers don't work
« Reply #2 on: March 02, 2007, 04:33:36 PM »
Here's the motors specs:

10 Volts
5 Amps
1.8 degree
1.5 Ohms

For the control, I don't know what you mean?
I have HobbyCNC board (3-axis), Mach3 software. Nothing else because I don't want to spend money before I get does motors to work.

Hood

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Re: Big steppers don't work
« Reply #3 on: March 02, 2007, 05:51:42 PM »
Just looked at the Hobby CNC  board it says 3Amp Max per phase.
Hood

Offline Chip

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Re: Big steppers don't work
« Reply #4 on: March 02, 2007, 06:47:49 PM »
Hi, tk421

Don't know what type of machine you planing on building.

But most steppers need up to 10 times the voltage rating to run them properly.

If this is the specs. on your board.

# 4 Axis Unipolar Chopper control. NO "Ballast" resistors required!
# Individual OR simultaneous control of 2/4 Phase Stepper Motors.
# Accepts 5, 6, or 8 wire stepper motors only.
# 42VDC maximum input voltage, 12VDC minimum input voltage. 24VDC Minimum Recommended Voltage.
# 3.0 Amps Maximum per Phase, 500ma (.5A) minimum. Each axis adjustable throughout this range.
# 1/2,1/4, 1/8, and 1/16 Microstepping .

You need to have a power supply around 40-45 volts and steppers with a rating of around 3 volts 3 amps, check the rating of your small steppers.

For the steppers you described, you really need to use a driver / control box, like the Gecko drives, there rated at 90 volts and up to 7 amp's, selectable amp setting.

The way steppers work, Voltage drives the Amprage the control boxes limit the current, the faster the stepper rotates the amp's drop off

for a give voltage the box allows an increases in the voltage to keep the amps at the max amp rating.

This allows the stepper to maintain it's Torque at higher speeds, which is limited by the max voltage of your power supply.

At rest the voltage on steppers is very low, the control box limits the amps to a safe amps value as not to burn up your steppers.

Let us now if you have more questions.

Hope this makes sense, Chip



Re: Big steppers don't work
« Reply #5 on: March 02, 2007, 07:03:54 PM »
Thanks guys

It makes a lot of sense now. I thought I was curse or something. ;)

Thanks again for your time.
Re: Big steppers don't work
« Reply #6 on: April 07, 2010, 11:08:30 AM »
HELLO,
  MY QUESTION IS ABOUT MICRO STEPPING. IS MICROSTEPPING A FUNCTION CONTROLED BY MACH, THE BREAKOUT BOARD, THE MOTOR, OR SOMETHING ELSE?  I AM BUILDING A CNC ROUTER , ( A PROTOTYPE TO LEARN BEFORE BUILDING THE BIG MONSTER),  I HAVE A MTA 100 MASS TERMINATION CARD, EZ PLUG STEPPER CARD W/ GECKO 203 DRIVES . MY STEPPER MOTORS ARE FROM HOMESHOP CNC WITH THE FOLLOWING SPECS...
2 PHASE
STEP ANGLE 1.8
VOLTAGE 2.0
CURRENT 6.0 AMPS
4 WIRE
HOLDING TORQUE 520

POWER SUPPLY IS AN TEK 65 VDC
1/2" - 10 ACME LEAD SCREWS.
WHEN I TESTED MY MOTORS WITH 2000 STEPS IN MACH, THEY SOUNDED GOOD. NOW THAT I HAVE THEM ON MY TABLE AND HAVE CALIBRATED THEM USING MACH IT SHOWED MY SETTING NEEDED TO BE 21333.00 STEPS. WHEN I RUN A PROGRAM FROM THE MACH WIZARDS OR EVEN JOG MY MOTORS THEY DON'T SOUND GOOD AND THEY GET HUNG UP. DOES THIS HAVE ANYTHING  TO DO WITH MICRO STEPPING. THE PROMO ON MY MOTORS SAY LOW COST MICRO STEPPING JUST GOT BETTER.
LOST AND CONFUSED, PLEASE HELP
 THANKS, CRAIG

Offline Hood

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Re: Big steppers don't work
« Reply #7 on: April 07, 2010, 01:45:32 PM »
If your motors are connected direct to the screws then you should have 20,000 steps per unit (200 steps for motor x 10 micro steps of drive x ten turn to a unit)
 The likely cause for  your motors sounding bad and missing steps  is that you need to tune them in motor tuning.
Hood