europian 220v - american 220v

[Unregistered]

my I use europian 220 V apl. with american 220 v standard?

[Ron]

Generally, yes you can use european 220V appliances on US 240V circuits.
Some devices such as clocks will not operate properly. Motorized appliances will spin 1/6th slower.

[Homer]

I think that you mean 1/5th faster.

A European (50Hz) motorized device, when powered by an American 60Hz supply, will spin 1/5th faster.

An American (60Hz) motorized device, when powered by a European 50Hz supply, will spin 1/6th slower.

Homer

[Guido]

I think that you mean 1/5th faster.

A European (50Hz) motorized device, when powered by an American 60Hz supply, will spin 1/5th faster.

An American (60Hz) motorized device, when powered by a European 50Hz supply, will spin 1/6th slower.

Homer
This got me thinking.
Theoretically speaking here, say I have a 1-phase motor 1HP, 1000RPM no load and want it to spin at 800 RPM. If I send it to a shop, what do they need to do to get it to spin slower? Forget about cost, practicality, etc.
I'm just trying to figure out what's the internal difference between a 1000 RPM motor, and a 800 RPM motor (all else being equal). More/less coil windings? Wire size? Etc.

[joed]

From my old college text books

pole =120x freq/rpm

so your answer would be
At 1000 rpm the pole would be 120 x 60/1000 = 7.2 poles impossible to build

But to compare at 800 rpm

120x60/800 = 9 poles

The more poles the slower it turns.

[Homer]

...Theoretically speaking here, say I have a 1-phase motor 1HP, 1000RPM no load and want it to spin at 800 RPM...As Joe pointed out, it's not possible to build a motor that has a synchronous speed of 1000RPM.

RPM = (60 x Line Frequency) / (Number of Pairs of Poles)

The 60 is for 60 seconds in a minute.

The Line Frequency is 60Hz in North America and 50Hz in Europe.

Motors built for North America will have synchronous speeds of 3600RPM, 1800RPM, 1200RPM, etc. with the 4 pole 1800RPM being most common (2 pairs of poles).

Motors built for Europe will have synchronous speeds of 3000RPM, 1500RPM, 1000RPM, etc. with the 4 pole 1500RPM being most common (2 pairs of poles).

So, in order to get 800RPM you could use an 1800RPM motor with a VFD (variable frequency drive) to change the line frequency from 60Hz down to 26.7Hz or you could simply use an 1800RPM motor with a 9:4 gear box.

Furthermore, an induction motor built with a synchronous speed of 1800RPM is usually plated as a 1750RPM motor at full load as the speed will drop with loading.

Homer

[mdshunk]

So, in order to get 1000RPM you could use an 1800RPM motor with a VFD (variable frequency drive) to change the line frequency from 60Hz down to 33.3Hz or you could simply use an 1800RPM motor with a 9:5 gear box.

Homer

Posts like this make me smile ear to ear! This is the bread and butter of many industrial engineers. Homer is apparently an old hand at these situations. Good job. (Do I sound like Ohm now, with my cheerleading?)

[Roger]

In my old plant our converyor system had many 3 phase 480 volt motors but the system was built a little before the advent of VFD's. We always had to use gear reducers (they cost three times a new motor's cost) to get the correct rpm's. Nice to see this info on the math that makes for the determination for correct rpm's.

[mdshunk]

In my old plant our converyor system had many 3 phase 480 volt motors but the system was built a little before the advent of VFD's. We always had to use gear reducers (they cost three times a new motor's cost) to get the correct rpm's. Nice to see this info on the math that makes for the determination for correct rpm's.

Were some of your conveyors also driven by large overhead leather belts turned by a large water wheel in the Rouge River? :D

[Roger]

Were some of your conveyors also driven by large overhead leather belts turned by a large water wheel in the Rouge River? :D
No we got rid of those in the late 70's

[Guido]

Motors built for North America will have synchronous speeds of 3600RPM, 1800RPM, 1200RPM, etc. with the 4 pole 1800RPM being most common (2 pairs of poles).
Oh OK, I didn't know that.

What's the physical difference between a European motor and a North American motor? I now understand why a motor will change RPM running on 60HZ compared to 50HZ, but why will a European motor run at a different speed than an American motor if they're both run on American current?

[Homer]

What's the physical difference between a European motor and a North American motor?There is almost no difference.

RPM = (60 x Line Frequency) / (Number of Pairs of Poles)

A 4 pole motor operating in Europe has a speed of 60x50/2 = 1500 RPM.

The same 4 pole motor operating in America has a speed of 60x60/2 = 1800 RPM.

As stated earlier; 1500RPM is 1/6th slower than 1800RPM, and 1800RPM is 1/5th faster than 1500RPM.

I should state that there is a slight difference in the physical motor manufactured for 50Hz compared to 60Hz.

The Inductive Reactance (XL) of windings (Impedance) is less at 50Hz than at 60Hz. This means that a motor designed to run at 50Hz must have more windings on its stator compared to a motor designed to run at 60Hz to draw the same current under the same load conditions.

XL = 2*π*f*L

So a motor designed for 50Hz operation will draw slightly less current when fed with 60Hz.

Homer

[bobm]

Homer,

<So, in order to get 800RPM you could use an 1800RPM motor with a VFD (variable frequency drive) to change the line frequency from 60Hz down to 26.7Hz<

When I use my 3/8" variable speed drill, what is actually going on when I press the trigger? Is that a voltage change or an AC frequency change?

Thanks Bob

[Ohm1]

Posts like this make me smile ear to ear! This is the bread and butter of many industrial engineers. Homer is apparently an old hand at these situations. Good job. (Do I sound like Ohm now, with my cheerleading?)

Yeah, you are sounding a lot like me, if you like to see and compliment the achieved and accomplished!

[Homer]

When I use my 3/8" variable speed drill, what is actually going on when I press the trigger? Is that a voltage change or an AC frequency change?

Thanks BobIn this thread we were discussing AC Induction Motors. The cheapest and most common being the Squirrel Cage Induction Motor (SCIM). These motors will have an unloaded speed proportional to supply frequency and will slow down as load is added.

Small power tools such as variable speed drills use a different type of motor. They typically use a Universal Motor. This type has a commutator like a DC motor so it can accept AC. As such the speed will vary as the supply voltage is varied. This type of motor is only practical at very low fractional horse powers (HP).

Homer

[xkvator]

industrial engineers.
We could use an engineer or two like Homer at our plant.
Short engineer story...We have a motion activated roll up door made out of some type of vinyl - metal tubing on bottom - very fast up & down. has a sensor to reverse if it comes down on a towmotor(no pedestrians allowed).
the electricians were making some adjustments to the sensitivity of the door reverse - the engineer(with hardhat on) stood under the door to test it. it reversed...after it knocked him to the ground :D He told the electrician to adjust some more(i don't think he made any :D ) and try it again...same results :D . The electrician asked him "try again?"...He walked away.
i never laughed that hard before

[mdshunk]

it reversed...after it knocked him to the ground
WTF kind of "engineer" would do such a thing? For Pete's sake, roll a tool box or something under it... anything except a person. Jeeze...