Forums > General Discussion   Shooting the breeze...

Alternative to step down 110V transformer.

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Created by Macroscien > 9 months ago, 31 Jul 2019
Macroscien
QLD, 6808 posts
31 Jul 2019 12:56PM
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I have little nice US made tiller.
So far I run step down transformer, but it is a bit heavy.Electric motor is induction type.I wonder if I could use on of following instead of transformer:
1) Use diode. If use only one , then total current may be only half of 240, But never tried on induction motor.

2) Capacitor in series. Should limit amount of energy consumed by motor

3) Thyristor- like a popular dimmer type





Ian K
WA, 4155 posts
31 Jul 2019 11:08AM
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No, won't work, you can't beat that transformer.

Macroscien
QLD, 6808 posts
31 Jul 2019 1:35PM
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Ian K said..
No, won't work, you can't beat that transformer.


This guy is trying something, but only on light bulb.

Macroscien
QLD, 6808 posts
31 Jul 2019 1:44PM
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Ian K said..
No, won't work, you can't beat that transformer.



You are right about diode.Motor most likely will overheat quickly and burn.

cr4.globalspec.com/thread/12531/Double-speed-in-AC-motor-second-part

But I am still not sure about using starting capacitor in series to limit energy that motor could draw.

Crusoe
QLD, 1197 posts
31 Jul 2019 6:11PM
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Buy a second one for the misses. Connect them is series and way you go :) The gardening jobs done twice as fast.

kk
WA, 953 posts
31 Jul 2019 4:44PM
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Put a solar panel on it and away you go

Macroscien
QLD, 6808 posts
31 Jul 2019 8:49PM
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kk said..
Put a solar panel on it and away you go


AC not DC motor

kk
WA, 953 posts
31 Jul 2019 9:32PM
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Of course I was joking, maybe making fun, but the real question is why didn't you buy something fit for purpose in the first place?

nebbian
WA, 6277 posts
1 Aug 2019 8:22AM
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A couple of points:

1) The motor inside this is probably a "Universal" motor, which can run on DC just fine.
2) Using electronics to limit the voltage can be problematic with that sort of load.
3) Your best bet would be to replace the motor with a 240V version, it's not as hard as it sounds. Those motors are used everywhere, and there are surprisingly few variants.

Macroscien
QLD, 6808 posts
1 Aug 2019 1:56PM
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kk said..
Of course I was joking, maybe making fun, but the real question is why didn't you buy something fit for purpose in the first place?


Apparently I could not find any garden electric tilers in Australia 6 years ago.
I doubt that you could buy one now either.But they do such thing in USA.

Macroscien
QLD, 6808 posts
1 Aug 2019 2:06PM
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nebbian said..
A couple of points:

1) The motor inside this is probably a "Universal" motor, which can run on DC just fine.
2) Using electronics to limit the voltage can be problematic with that sort of load.
3) Your best bet would be to replace the motor with a 240V version, it's not as hard as it sounds. Those motors are used everywhere, and there are surprisingly few variants.


1)I didn't open the casing to check but the motor is so quiet that I very doubt that is universal with brushes and fans.
3) Apparently I have similar advice from the best in electric engineers in the world- as I posted same question yesterday to experts website knowing everything from Aeronautical to Electronics, Engineering and 100 other scientific branches. That replacing motor could be the easiest. This days we have even more option with low voltage brushless motors that could run on batteries.
I am converting another small garden tractor now for fully electric and made already few self driving electric carts.
BTW the only Electric Auger 240V/ 1200W that you could buy in Australia is made for me specifically on order,
but I am not going this time to manufacture electric tillers . Augers where also only petrol driven , but when I want one, I needed to manufacture my owns.

nicephotog
NSW, 276 posts
1 Aug 2019 10:15PM
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The back of the device says 0.57Kw
so just get a 0.75KVa or 1.0KVa 2:1 transformer and "240v appliance resister to rate drop to 2Kw (load) 600w throughput with load and surge power" to hook into the socket side of the transformer winding (the smaller side) and hook the appliance pin pair to to the two larger transformer winding ends for step down volts.

nicephotog
NSW, 276 posts
2 Aug 2019 9:05AM
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Here's the better choice rather than throwing in manual dirty controls for the power.

3kw step down supply
www.careyou.com.au/p/brand-new-3000w-240v-to-110v-step-down-transformer/6302?gclid=EAIaIQobChMI19OSieTi4wIVl4BwCh2dWgPQEAQYAyABEgIPOPD_BwE

pweedas
WA, 4642 posts
2 Aug 2019 2:52PM
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nebbian said..
A couple of points:

1) The motor inside this is probably a "Universal" motor, which can run on DC just fine.
2) Using electronics to limit the voltage can be problematic with that sort of load.
3) Your best bet would be to replace the motor with a 240V version, it's not as hard as it sounds. Those motors are used everywhere, and there are surprisingly few variants.


Yes, almost certainly an ordinary all garden variety universal motor, same as in the electric drill etc, because the nameplate indicates a maximum RPM of 4541 rpm.

Induction motors run at an RPM a little below synchronous rpm.
Synchronous rpm at 60hz is 1800 for 4 pole motors or 3600 for 2 pole motors.
If it was an induction motor the rpm would be a little less than this, say 1725 for 4 pole or 1725 for 2 pole.
They have to be a little under synchronous rpm to maintain a 'slip angle' which is what makes that type of motor turn.

Neither of these is close to the 4541 rpm on the name plate so it's not an induction motor.
Thus the motor must be a universal motor and will be quite happy on a DC supply, but not at 250 volts dc.

And nebbian rightly states, there will be problems if you run a 110 volt electric motor on a chopped 240 AC volt supply. i.e scr or triac controlled input voltage. It will end up cooking the commutator because the full 240 volt cycle will regularly be dumped onto the commutator via the brushes. 240 volts ac is 385 volt peak. It will arc over the commutator segments and fry.
Be sure to have your sausages ready and a toasting fork.

However, if it was a 110 volt DC supply made by rectifying the 240 volt AC supply and then run that through a chopper supply to generate smooth and stable 110 volts DC in the same way that your computer supply generates the various DC voltages required, it would work fine, but do you really want to do all that work?

The best options, use a step down transformer at the power outlet as per that suggested above, or change the motor.

Oh,.. and don't get yourself electroluxed. oops,.. I mean

I'm serious about the electric risk. MAKE SURE YOU UNPLUG ANYTHING YOU ARE WORKIING ON.

Don't forget to post pictures of the results.

FormulaNova
WA, 15084 posts
2 Aug 2019 3:39PM
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Why don't you just leave the transformer right next to the power point it plugs into. Its not like you can move the powerpoint. The transformer is heavy? Buy a trolley from SuperCheap and push it around. Simple. Cheap. Easy, Safe.



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Forums > General Discussion   Shooting the breeze...


"Alternative to step down 110V transformer." started by Macroscien