Author Topic: dc05 removing elbow (Read 12145 times)

mojo · « **Reply #15 on:** August 25, 2015, 11:55:40 am »

I did wonder because we are dealing here with alternative current which does not have polarity like direct current.

It turns out that after opening it for checking what motor version I had, I connected the wires reversed. before I replaced the new motor I checked the old motor, with wires crossed, and it did suck which suggests that it was spinning the correct way not reversed.

Tech12 · « **Reply #16 on:** August 25, 2015, 12:55:14 pm »

Hi Mojo: Your right it would still be spinning in the same direction, the motor is a Single phase uni A/C (Alternating current) motor. Reversing the wiring to the motor won't cause it to run backwards or draw excess current, cause any problem with the brushes or cause it to smoke or burn out.

There are many motorised appliances in daily use where people have wired the plug in reverse & they still work with no detrimental effects.

MVacs · « **Reply #17 on:** August 25, 2015, 04:06:44 pm »

Quote from: Tech12 on August 25, 2015, 12:55:14 pm

Reversing the wiring to the motor won't cause it to run backwards

Thats me corrected then.

Tech12 · « **Reply #18 on:** August 25, 2015, 04:29:26 pm »

Sorry Stu the reply wasn't aimed at you or anyone in particular, I didn't realise it was you that said it. Didn't intend to cause any offence.
It's not just you that thought that, a lot of people do. Including some Sparkies I've met on the job, a lot of courses don't even teach basic motor theory.

MVacs · « **Reply #19 on:** August 25, 2015, 04:35:23 pm »

We all live and learn. Not that we make a habit of connecting motors the wrong way round you see.

Might have been DC or 12v ones I recall doing this with years ago. I recall it worked with some type of motor........

Tech12 · « **Reply #20 on:** August 25, 2015, 04:43:36 pm »

Yep it definitely reverses DC motors and some AC motors but not this particular type. Your dead right we all live & learn, life would be boring otherwise

MVacs · « **Reply #21 on:** August 25, 2015, 11:12:23 pm »

Quote from: Tech12 on August 25, 2015, 04:43:36 pm

Yep it definitely reverses DC motors and some AC motors but not this particular type.

Its coming back, AC with 4 leads on, stuff like sewing machines.....DC too..... AC reverse otherwise via an A bridge, or is it a H bridge? I forgot. Yikes, that was years ago. Yeah, I don't need to remember that stuff now.

Quote from: Tech12 on August 25, 2015, 04:43:36 pm

Your dead right we all live & learn, life would be boring otherwise

Why we like you here coz you know this stuff.

Madrat · « **Reply #22 on:** August 25, 2015, 11:24:41 pm »

Witchcraft

I still think my inverter is full of fairy dust

Tech12 · « **Reply #23 on:** August 26, 2015, 09:02:19 am »

Quote from: MVacs

Why we like you here coz you know this stuff.

Thanks.

Your right we don't need to remember most motor theory, things like Induction motors, 3 phase & reverse windings etc. Don't think Dyson are going to start fitting them any time soon & my brain's cluttered enough as it is.