A 240 Volts Drill Work Over to 120 Volts

You can wind your own crude transformer, but hardly seems worth it....

http://www.ehow.com/how_7446316_120-volt-240-volt.html

Duck 'er comes Lyn...!

Thanks. I didn't expect a guideline on how make a dangerous bad transformer. I am also not familiar with the used "magnetic" wire. D.

It's not magnetic, it's magnet wire....You wanted cheap....this is about as cheap as it gets....

http://www.amazon.com/b?ie=UTF8&node=310354011

What a CROCK OF DO-DO!

I can't believe they publish that crap.

There, how's that?

Reconnect it as a shunt motor you had better have plenty of fuses in stock. The field won't have enough impedance to control the current.

thats not a problem, just wrap the fuse in aluminum foil

LOL...

.

Maybe you just need to get some high speed drills.

I have been hoping to get some motivation to make this drill useful. Seems like a transformer, a L1- L2 supply connection or a garbage bin to dispose the drill to are some options.

It is a drill Bosch 350- 2 and if someone picks it up here, it is free.

Suggest just to try it out on 120 V.

Chances are you no need to ask this question again!

Its worth exactly what you paid for it!

Or E-bay it and make some buck! No need to tell the detail of the 240V!

GET OUT OF THE POOL BEFORE TRYING IT!

The drill is 240V 50Hz, you want to use it on 120V 60Hz? I think I see magic smoke in your future.

Sorry to disagree:

When I arrived in the 60 Hz zone, all my tools (and that was a whole bunch for 15 workers were 50 Hz) They have been used and still are (the ones that were not stolen) and are in good shape after 17 years. Makes like Bosch, AEG, Makita, Skill, Fein. On the contrary; machines of US origin (125 Volts) like Milwaukee fall like flies.

The RPM's do not seem considerable higher, because all have series universal motors and the armatures are over sized for 50 Hz. Not one burnt out. Just classic repairs, brushes and bearings.

We are talking of about 200 electrical tools in total.

Ok, maybe no magic smoke, but at the lower voltage you probably won't have the original torque.

It appears that it is adequate.....and a very cheap method!!

No magic smoke, that won't happen as its a universal motor, but due to only getting half the voltage, it will run slower, but should still be very useable....it would last forever....

Now if you took a US drill and plugged it into the UK mains, magic smoke would appear!!!

But he could change the connectors and wire it over the two hot legs so that it would get around 240 volts or slightly less......may I suggest that it is NOT done using standard 120 volt connectors. I am sure that the USA has special connectors for when the two hot wires are used, then he needs a long cable to get the drill to where he needs to work!! A waste of time, drills are cheap, especially in the US....

The cheap version is to accept that the drill will run slower on 120VAC and use it anywhere.....slower!!

By the way, universal motors are not frequency affected, as they are basically an old fashioned DC motor....but as the rotor and stator both get the AC at the same time "swinging around", the motor still continues in the same direction.....

But I don't want to give a long explanation of "why?" here.....that would be "Off Topic" I feel..

The easy and safe method would be to use a primary winding pair from a common 115/230:xx/xx transformer as a three wire voltage boosting transformer to get your 240 VAC form the 120 VAC lines.

Just set it up with the center tap of the 115/230 winding set as the common line from the 120 VAC primary so that you never have more than 120 VAC from either of the two line outputs to ground and you are good to go.

Also being the transformer would be working in an autotransformer configuration you only need a VA rating of half the tools wattage requirements to work properly which in your case any cheap 115/230 VAC primary 150 VA or slightly larger transformer, or multi volt lighting ballast for that matter, would be more than enough to handle your drill.

Thanks, I'll come back with results later.

Hi DVMDSC,

I USE American tools here in Europe and vice a versa, depending on where I am, these are cheap and reliable. This is the first model I pulled op on Amazon.

http://www.amazon.com/Voltage-Converter-From-220-240/dp/B001ES8YY6

Good Luck,

Expat07

To rewire your 240v series motor to a 120v shunt motor, you are assuming that the 240 v is divided equally between armature and field. If not, one is going to draw more current as shunt motor.

However, a more important consideration is that the characteristics of shunt and series motors are different. In a series motor, when the motor is up to speed, the back emf limits the current, resulting in less torque at high speed, and limiting the top speed.

A shunt motor has a more or less constant torque (and current draw) at all speeds. Since a series wound motor draws heavy current at stall and much less up to speed, the windings may not be designed to draw a lot of current continuously as a shunt wound motor and it could burn out.

Absolutely correct.

See 12!

You state "I do not want to buy different coils. because that modification costs more than a new drill" but you are looking at costs both financial and frustration in doing any electrical changes or use with it in series with other devices. Besides that how do you know that the investment is going to work? It could be very dangerous or self destructive.

Save some money, save some risk, save time, and save your temper--> go buy a new one! You know it will work! Unless it is some exotic drill such as a 1/2" or 3/4" angle drill or a magnetic base it is cheaper to buy new than to mess with this one. If the drill is an antique or has sentimental value to you, put it in a special storage container marked "Antique/Sentimental Tools".

If you still want to use the drill, tie the plug end of the cord onto the bow of a row boat and use it as an anchor.

Good Luck, Old Salt

I don't really need a new drill. It is just an exercise for here: or use it as an extra next to many I have (for drilling, screw driver etc..- less bits to change in repeated actions), or I might take it with me to Europe and make someone happy with it.

A series construction with something is certainly NOT going to work. Sorry that I even mentioned the bread toaster, (thought it could have been funny?)

The bread toaster is not going to add 125 Volts on top of the 125 V the grid provides.

I hope Solar Eagle has recovered, because on the pic. he provided, he looked like an upside down chicken already?

Hi All,

I have put a 125 Volts plug on the cord and it works pretty good.

I has even some respectable torque.

Thank you all for your time. D

If THE SERIES CONNECTED FIELD AND ARMATURE DROP THE SAME VOLTAGE WHEN OPERATING, WHICH THEY PROBABLY WON'T, THEN YOU CAN REWIRE THEM IN PARALLE3L FOR 120V OPERATION. OTHERWISE GET YOURSELF A TRANSFORMER OF SUFFICIENT KVA RATING. THERE ARE PLENTY ON THE MARKET...CLINT

It will rotate slower and its torque will be significantly lower. Give it a try, maybe you can use it.

Re-winding: it does not worth.

Step-up transformer: to expensive

Frequency: not a matter, it could work with DC as well.

Do NOT try to convert it to shunt motor: the stator will burn! Inn normal (series) operation the stator current is limited by the counter-induced Voltage of the rotor...

There's an echo in here.

Cheap as chips way is to get a second user motor and swap it.

As the guys have suggested a transformer is a good option. How useful it will be as a tool is for you to find out. The motor will run faster but is ulikely to catch fire which it likely would going 60Hz machine onto a European 50Hz supply.

Some one in a design office has carefully worked out the characteristics of the motor to be suitable and efficient with your machine. Seems a little crazy to try and run the machine on a supply it wasn't designed for. You are unlikely to get the best out of it.

Qgberci at 28 is a GA.

You need a series wound motor to ensure the armature reaction current and field current are in phase to produce the torque.

The torque is related to field strength, which is related to current, which is high at start up, ie stalled, which is related to the supply voltage. Enough torque will cause the armature to speed up. As it does, the back emf reduces the field current, and hence the field strength, hence the torque, and hence a max speed is reached.

On no-load, ie, free running, the motor speeds up and reaches a maximum speed governed by the torque caused by friction and windage loss.

On full-load, the torque imposed by the work device slows the motor to a steady speed (the maximum for that particular duty) where the current and voltage at a that maximum if sustained, causes the motor to heat up. Eventually to overheat and maybe burn out.

In practice you probably find the drill becomes too hot to hold before it burns out.

Using the drill on a lower voltage will limit the torque, which at any particular speed, slows the work rate, and thus the drill runs longer at full load, but at lower power.

The higher supply voltage will produce a higher torque if required - and a higher speed on lighter loads, or no-load. The 'weakened' file strength cause a motor to speed - it's to do with the armature having to rotate faster to generate the back-emf to reduce the current. Which in doing so, weakens the field further, causing the armature to go even faster.

Slightly off topic, but relevant to series motors, in the old days (when I first started work) work-shop machines were often belt-driven from a common overhead pulley shaft, that itself was belt-driven by a DC motor at source.

We were called out to a motor breakdown. I was an apprentice, but basically my duties in those early days were not much more then errand-boy and tea-boy, in a look-and-learn position.

I can only recall what I saw. The motor had stopped due to a starter problem. The urgency to get the machines running meant the starter had to be 'fixed' (somehow), and so it was.

I was not there at the time, but later we were told a major disaster had occurred. It seems the main drive belt had broken and the motor running on no-load reached high speed. The starter, having been 'fixed' (unwittingly I guess) did not provide over-speed protection.

The series motor being short in length, but large diameter, ran unchecked to such a high speed on no-load that the centrifugal force caused the armature coils to fly apart. This caused the motor to instantly seize up. The momentum ripped the motor offs it's base and it bowled down the workshop skittling everything on it's way. I have no memory of anyone being hurt or the consequences.

20 9V batteries in series should run your universal at near full power.