# Why does rectifier bridge feed 1-phase motor?



## MDShunk (Jan 7, 2007)

You sure it wasn't a DC motor, like our 555 benders have?


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## swimmer (Mar 19, 2011)

Yes I'm sure. I read the spec on the motor. Also, there is no capacitor so it would be pretty choppy DC.


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## swimmer (Mar 19, 2011)

It must serve either:
1. Starting function for the single phase AC motor. 
AND / OR
2. Reversing function.


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## MDShunk (Jan 7, 2007)

Then it's a brushed AC motor. Did you notice brush holders?


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## swimmer (Mar 19, 2011)

MDShunk said:


> Then it's a brushed AC motor. Did you notice brush holders?


No, I didn't notice brush holders. All I know is that the motor had 2 input wires and ground.


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## bkmichael65 (Mar 25, 2013)

swimmer said:


> A plumber friend had a motorized snake that wasn't working.
> He had the motor control box disassembled.
> 
> This is what was inside:
> ...


I'm pretty sure that those use DC permanent magnet motors. If the motor's only feed is coming from that rectified dc fed reversing switch, then you have a dc motor


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## swimmer (Mar 19, 2011)

bkmichael65 said:


> I'm pretty sure that those use DC permanent magnet motors. If the motor's only feed is coming from that rectified dc fed reversing switch, then you have a dc motor


Mistake a D for an A? Maybe I need new glasses.

I'll see if I can get a picture.


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## telsa (May 22, 2015)

swimmer said:


> Yes I'm sure. I read the spec on the motor. Also, there is no capacitor so it would be pretty choppy DC.


The motor windings (induction circuit) provide their own wave buffering -- without further ado. 

BTW, the device, itself, is a CLASSIC DC traction load... just like the 555 bender.


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## bkmichael65 (Mar 25, 2013)

swimmer said:


> Mistake a D for an A? Maybe I need new glasses.
> 
> I'll see if I can get a picture.


It's been years since I could read nameplates without a magnifying glass. I feel your pain


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## bkmichael65 (Mar 25, 2013)

swimmer said:


> Mistake a D for an A? Maybe I need new glasses.
> 
> I'll see if I can get a picture.


You may have also mistaken 1/5 HP for 1.5 HP. That much horsepower would probably rip the pipes out of the wall


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## JRaef (Mar 23, 2009)

A "Universal" motor is referred to (and nameplated) as an AC motor, but runs as a DC motor and can accept either AC or DC. This is what is in things like portable drills, which if you think about it is a lot like a snake machine. Using the rectifier ahead of the motor allows the reversing and variable speed capability to take place outside of the motor itself, which on something that might be getting wet is what you want to do. So the motor likely has brushes, but is sealed up to avoid "water" getting in when snaking out the nasty pipes.


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## triden (Jun 13, 2012)

Probably a brushless DC motor which is really a 3-phase AC motor with brains to chop up the DC into a varying frequency output AC.


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## JRaef (Mar 23, 2009)

triden said:


> Probably a brushless DC motor which is really a 3-phase AC motor with brains to chop up the DC into a varying frequency output AC.


The controls would be a lot more than just a rectifier... plus, it's a freaking plumber's snake... That would make the snake smarter than the plumber!


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## Jlarson (Jun 28, 2009)

Lol a brushless snake.


I bet Milwaukee is working on a M18 fuel version though.


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## triden (Jun 13, 2012)

JRaef said:


> The controls would be a lot more than just a rectifier... plus, it's a freaking plumber's snake... That would make the snake smarter than the plumber!


:thumbup:

But to close, I missed the part where all he found was a rectifier - was thinking that maybe there were a couple more goodies in there such as a uC and some mosfets.



Jlarson said:


> Lol a brushless snake.
> 
> 
> I bet Milwaukee is working on a M18 fuel version though.


Milwaukee, being a Chinese multinational, is probably trying to imitate anything they can! Hell, somewhere in China is an Ikea that's not actually Ikea...you just wouldn't ever know it.


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## GrayHair (Jan 14, 2013)

I stopped by the home of someone who had recently left the company to pick up company property he had forgotten about. He was trying to clear a clogged toilet with a plunger, so I suggested a snake.

I ran into him several months later and he informed me that my suggestion had caused him untold grief. His wife spent two months telling him exactly what would and would-not happen if he brought a snake anywhere near that house! :laughing:


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## swimmer (Mar 19, 2011)

MDShunk said:


> You sure it wasn't a DC motor, like our 555 benders have?



MD Shunk nailed it from the start.
I read 115VAC input and then quit reading.
Also interpretted 1/12 as 1 1/2 and didn't notice "@RECTIFIED"

Time for new glasses


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## macmikeman (Jan 23, 2007)

It is dangerous for a man of my advanced age to do a headstand you know.


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## telsa (May 22, 2015)

There's you problem right off: the juice is leaking out because it's upside down!

I wish everything was that easy to figure out.


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## paulengr (Oct 8, 2017)

priyankagupta said:


> You could have a superior drive adjust setup, however that is not your issue. You can influence these VFD's to perform like impeccably cogged servo drives regardless you'l have chain extend.
> 
> Your issue is your desires. Having to strain a pull chain without precedent for a long time a year back, of course a week ago, that is entirely condemned great. You had no wonderful chain wear (extend) for a long time, at that point you needed to pressure again a year later. Sounds significantly ordinary.


Jabberwocky on an old thread?

Sent from my SM-T350 using Tapatalk


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## joebanana (Dec 21, 2010)

telsa said:


> There's you problem right off: the juice is leaking out because it's upside down!
> 
> I wish everything was that easy to figure out.


You definitely don't want the "juice" from one of those things to get on ya.


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## joebanana (Dec 21, 2010)

priyankagupta said:


> You could have a superior drive adjust setup, however that is not your issue. You can influence these VFD's to perform like impeccably cogged servo drives regardless you'l have chain extend.
> 
> Your issue is your desires. Having to strain a pull chain without precedent for a long time a year back, of course a week ago, that is entirely condemned great. You had no wonderful chain wear (extend) for a long time, at that point you needed to pressure again a year later. Sounds significantly ordinary.


????????????????????????????????????? :vs_whistle:


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## emtnut (Mar 1, 2015)

priyankagupta said:


> Your issue is your desires. Having to pull chain


You may be onto something.
I remember having to pull my chain continuously because of my desires !



priyankagupta said:


> that is entirely condemned


And I heard it causes pimples too.
:biggrin:


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## micromind (Aug 11, 2007)

Just for info, if DC is applied to an AC induction motor, it'll lock the shaft. 

A lot of VFDs have a feature called DC Braking and it uses this very principal to stop a motor as quickly as needed. Some VFDs have a feature called DC Hold. This is where DC is applied continuously and the shaft is locked continuously. 

If enough DC is applied, it could easily be termed 'DC Breaking'.......it'll stop the shaft quickly enough to bust stuff.


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