electric motor help

[mart_1986]

im trying to get a 7.2volt motor run forwards and in reverse i took the motor out a cordless drill but when i wire it up it doesnt run how can i get it to work the motor 100% works

 

[BrownOut]

You need a double-pole, double-throw switch. Wire the voltage reverse from one "throw" to the other, ie, what connects to '+' on one throw connects to '-' on the other, and visa-versa.

 

[mart_1986]

i wired it to 2 switches push in 1's i wired it up 2 the motor had 2 lives and 2 neturals every time i pushed the button nothing happened so i removed 1 netural 1 button worked this is whats confussing me why wont it it work when i have to neturals do i need a diodes to stop it from picking the other netural up

 

[BrownOut]

I can't visualize how you connected it without a drawing. Here is what I was talking about:

 

[mart_1986]

here a quick drawing its not the best lol

**broken link removed**

 

[BrownOut]

That won't work. Use my drawing instead.

 

[mart_1986]

is there away to get it work with them push switches as i drilled the holes in my case now?

 

[BrownOut]

The method shown is the only way I would suggest to do it.

 

[mart_1986]

ok thanks for your help

 

[Gobbledok]

What pushbuttons are you using? The current required by the motor (especially on start-up) probably exceeds the current limit of your pushbuttons.

 

[Hero999]

It's possible to use push button switches, but you either need to use relays as well or SPDT push button switches; these will have the same contact configuration as the relays in the schematic shown below.

**broken link removed**

 

[kinarfi]

here a quick drawing its not the best lol

**broken link removed**

The drawing has line and neutral written on it, are you trying to run it on ac or dc?

 

[Hero999]

I think he means positive and negative.

Live and neutral are used for AC circuits, live is also sometimes called, phase, line or in the US hot, probably because it can burn you. Neutral is often called return or 0V.

 

[kinarfi]

I think he means positive and negative.

Live and neutral are used for AC circuits, live is also sometimes called, phase, line or in the US hot, probably because it can burn you. Neutral is often called return or 0V.

I imagine your correct, but unless the motor is dead, when you hook it to 7.2 D.C. as is #1, it will run, if hooked to A.C., it won't run, so I thought I would ask just to be sure.

According some books, we all had the same language once, until some guy wanted a big tower, Babble, Too bad. If you don't understand, don't worry.
kinarfi

 

[Hero999]

It's a DC motor so of course it won't run off AC which will overheat it, if it's left connected for too long.

 

[shortbus=]

I always was told a brush motor was a universal motor. Would run on AC or DC as long as voltage was correct. Or close.

 

[Hero999]

A permanent magnet motor is not a universal motor and requires DC to run.

A universal motor can run on either AC or DC because the field in both the stator and armature is reversed when the current is reversed.

In a permanent magnet motor, the stator field remains the same when the current is reversed so the shaft direction is also reversed.

 

[kinarfi]

it might be said that all universal motor are brushed, but not all brushed motors are universal, those with permanent magnet fields. Universals have wound rotor and wound fields, and like hero said, as the current reverses, so does the fields in both the armature and the field. A word of warning about universal motors that have variable speed on DC, use full power so you bypass the electronics since they go full on anyway.
Kinarfi

 

[BrownOut]

A word of warning about universal motors that have variable speed on DC, use full power so you bypass the electronics since they go full on anyway.
Kinarfi

Please explain this comment. Are you saying to not control a universal motor speed if you're using DC?

 

[kinarfi]

Please explain this comment. Are you saying to not control a universal motor speed if you're using DC?

On many gas powered welding machines, there is a 120 vdc outlet for plugging drills and grinders into. I you plug a Milwaukee (for example) variable speed drill into it, as soon as you pull the trigger just a little, it goes full speed because the Triac fires and stays fired waiting for the zero crossing which will never come, so the triac is handling the current. If you pull the trigger full on, you have bypassed the triac and have a metal to metal contact path. The triac may be tough enough to handle the load, but why chance it. So unless you have a different type of speed control which is designed for DC, the common A C variable speed control in most A C tools won't work any way.
Kinarfi