Sorting out the steps

[Shanghyd]

Hi everyone,
I've been at sorting out my new (to me) motors and I'm having difficulties with the sequence.

The motors are SloSyn M061-LE-517 - 5.0 Volts, 1.0 amp, 60 oz hold, 200 steps

The wire colors are
Green
Green/White
Red
Red/White

Orange
White/Black

Black
White

The orange and white/black are joined at the connector
The black and white are joined at the connector
The connector ends up being a 6 plug even though 8 wires come out of the motor.
I've figured out that the two sets of wires joined at the connector are common V+ wires. (correct me if I am wrong please)

I've hooked up 12v to the two common pins and then grounded each of the other wires one at a time. (grounding the pin that comes out of the motor then removing the ground jumper wire after seeing the result.
To get 4 steps in the clockwise direction I touch green/wht, green, red/white, red.

I'm using this schematic
http://www.aaroncake.net/circuits/stepper.gif

I've got the circuit sorted out. I had led's hooked to the output pins after the resistors coming from the 4027 to see what the sequence was.
The sequence lit up the led's like this during stepping:
step 1 (relative to where you begin keeping track I suppose)
15 and 1 on

step 2
14 and 1 on

step 3
14 and 2 on

step 4
15 and 2 on

I hooked up the transistors and stepper wires and used TurboCNC to jog the motor. The motor buzzed, rattled, hummed and danced around but didn't spin.
I tried just about every different wire sequence but can't accidently get the right sequence.

Does anyone know the correct wire sequence or maybe a clue as to where I'm going wrong. I might be missing something that you experts can see right away.
Thanks in advance for any help

[jeffs555]

If that is a 5 volt motor, the first thing is to stop applying 12 volts without some form of current limiting. You could damage the motors if you haven't already. You would need resistors in series with the common wires from the motor to use that driver with 12 volts on 5 volt motors.

From your tests with applying voltage to the common and grounding the other wires, it would seem that red is paired with green, and red/white is paired with green/white. As long as you connect the red and green wires to one pair of transistors, and the other wires to the other pair of transistors, it should work.

Is the logic in your circuit really connected to 12 volts? If so, how are you connecting it to your computer? You can't drive 12 volt cmos logic directly from a parallel port.

[Shanghyd]

I'm using a computer power supply.
5 volts (red and black) is driving the logic circuit and 12 volts <i>was</i> going to the stepper motor commons.
I dont have the diodes as shown in the circuit. Would that make a difference in rotating the motor?

[jeffs555]

The diodes are there to protect the output transistors. Without the diodes, you could have thousands of volts across the transistors which are probably rated for less than 100 volts.

Your main problem is likely that you don't have enough drive to the output transistors. Testing with LED's would show that the circuit is wired correctly, but LED's don't require much current. It is probable that the output transistors don't have enough drive to supply the current required by the motor. What is the part number of the output transistors, and what value are the base resistors? What is the part number of the logic chips?

The circuit shows single transistors for the outputs, when they should be darlingtons. Standard cmos logic will only supply a few miliamps, and a normal power transistor would have a current gain of 50 or less. You would be lucky to get 100ma from the outputs without darlingtons.

[Shanghyd]

First chip
MC14070BCP
Motorola FFQR8822

Second chip
MC14027BCP
FFPJ9325

Transistors
5115509
BD649

Resistors are 1K

That's interesting. I don't know where the BD649's came from. I went shopping for all the parts and had TIP122 on my list which is wrong too.
The guy at the store cross referenced the TIP122 and found the 649.
I can't remember why the TIP122 was on my list.

I'll go pickup some tip31's or try to recover some from the electronics I have sitting around here.

[jeffs555]

You definately don't want TIP31's, they are not darlington and only have a gain of about 50. The BD649 are darlingtons and do appear to be equivalent to the TIP122 which is what you want. They have a current gain over 1000 so they should work fine. The 1k base resistors may be a little high, 500 ohms would give a little more drive current, but now that I know you are using darlingtons, drive current is probably not the problem.

I am not really familiar with turbocnc, but there should be settings for acceleration and jog rate. I would try slowing those way down. Most likely you are just trying to accelerate the motors faster than they will go.

[Shanghyd]

I have the motor spinning now.
It was a combination of settings in Turbo CNC and also a matter of completely seperating the logic power supply from the motor power supply.

The motors aren't very strong though. They seem a little slower than I expected.

[jeffs555]

At 60 oz-in they are not very strong motors, but should be fine for a small machine. The speed can be improved by increasing the motor supply voltage. Speed is directly proportional to supply voltage. Going to a 24 volt motor supply would give you about 5 times the speed that 5volts will. You will need current limiting resistors in the common wires to the motors to use a higher voltage with that drive. If you search this forum, I believe someone has a calculator to compute the required resistors.