Watch out when ordering small stepper Motors, 28BYJ-48

Recently I ordered many 28BYJ-48 small stepper motors.

I have since found out that not all of them spin the same direction when driven by the same pulse sequence -
91 of mine turned clockwise, and 5 turned counterwise!
The markings on the majority were the same - 15031801 on the label.

The other 5 had a different number, something that looked like an 8 digit serial number. Mine all happened to be 91416xxx, with 5 different numbers for xxx.

So if you're ordering multiples of these, check the pictures - don't mix 15031801s from one source and unique numbers from another source.
It's certainly handleable in software, but I have enough going on that I didn't want to deal with having to treat 5 motors differently than the rest. The 5 are being returned and replacements have been ordered.

I suppose I could have also depinned the connecters and rearranged them, but as I noted, I am busy enough already.

Were the wires in the connector the same? Colour and position?

Good morning my friends,

Myself, if I was to purchase about 100 units of any product. I would be specific of the item/s ordered. I would send a confirmation email regarding my order... part number, batch number, order number, serial number. It is really up to you to give the suppliers the details they need to fill an order. I would send back items that don't meet my requirements.

Bought them from Amazon, no one supplier had that many, so multiple sites was the only option.

They looked identical - same green ULN2003 card, same wire colors & same order on the connector.
Only thing different was the 15031801 vs 91416xxx.

Isn’t there a simple wiring change that will switch the direction of a stepper?

westfw:
Isn’t there a simple wiring change that will switch the direction of a stepper?

What a strange question!

Just exchange any two end connections of any single winding. :grinning:

Paul__B:
What a strange question!

Just exchange any two end connections of any single winding. :grinning:

If you are not using a keyed socket, turning the connecter 180 degrees is often sufficient, a lot of cables are wired intentionally to allow that.

I have since found out that not all of them spin the same direction when driven by the same pulse sequence - 91 of mine turned clockwise, and 5 turned counterwise!

The color coding of the motor wires is inconsistent. People noticed that a long time ago.

Some motors won't work at all until you swap the wires around correctly.