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US kitchen blenders on 230V - modification w/o using transformers?

Have bought a nice collection of vintage waring blenders (mainly one-speed, a few multi speed ones, roughly 400w power on all of them). They are currently sitting in my sisters small flat in Miami (poor girl!) but the intention is to have them transported to Norway somehow. Blenders only became popular in norway in the second half of the nineties maybe... so these still working antiques would be super exotic over here.

But as in most (all?) of europe the electric supply here is 230V/50Hz. The blenders are rated 115V, 3A, 25-60cycles (the ones from the

1940s-50s).

I have looked into power transformers and cheap converters like this one:

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The one above is small neat and affordable but i have read that these may not be so great for motorised appliances. The alternative is then a bulky and relatively expensive transformers which will not look very at home on the kitchen bench. If only the blender itself could be modified that would be just so much more elegant!

During my web searches i have understood that the blender motors are probably of the universal type (AC/DC) with carbon brushes. And in one article i came across a link to a product page:

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B-pak motor is here listed as voltage 100-255 VAC. Could it be that such motors in general are suitable to run on very different voltages and that the blenders may work straight from the net by only changing the plug or some internal widget? Guess not....

BUT: Taking the one-speed toggle switch blender of the 1940s as an example. What modifications are likely to be necessary in order to have it run on 220v? Would it be more tricky to convert the multispeed blenders?

I immediately imagine that such a conversion involves reducing the number of windings on the rotor? But would that do the trick or are there other things that need sorting out in order to acchieve proper operation? If replacing the windings is the way to go a formula for calculating number of windings and wire cross section would be deeply appreciated. Any things i should know about such operations (changing windings)? I am quite a handyman but unfortunately have no great knowledge about electrics....

Hope anyone can help out with this!

thanks!

kristian

Reply to
kristian
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Assuming you have got a proper transformer to step down the voltage to

120V., running a 60 hz motorized appliance on 50 Hz is going to run slower and draw more current at each step setting. Because of the lower reactance (opposition to current flow) at the lower frequency, the increased current is likely to overheat the motor coils if you run it for any length of time. (Or quite possibly, just for a few seconds...)

One trick to compensate for the overheating is to reduce the input voltage to the blenders by 10 to 20%. If you have a step down transformer that has taps, you could try running the blenders at 100 volts 50 hz instead of 120. (An alternative is to put a big power dropping resistor in series with the transformer secondary, but this can be dangerous and awkward. It would have to carry the current load and put out a lot of heat. Plus making it safely insulated would be difficult.)

I personally wouldn't recommend attempting to change the motor windings on a project like this, but if you can find similar motors that are designed for Euro 50 Hz 230 volts, swapping out the motor might be an option.

Beachcomber

Reply to
Beachcomber

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How about a UPS that takes the 220-50 and gives 120-60. Might be the easiest way to do it. Changing the motors will be a pain and way expensive. If your planning on selling them then you may have some real issues.

Reply to
SQLit

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Thanks!

Are there really convenient ways of changing the frequency to 60Hz?? Have looked around for transformers but don't think i've seen such a thing... As for the frequency, someone suggested earlier (or in a different group?) that the shift from 60Hz to 50Hz would not only slow down the motor and reduce the torque but also pose possibly hazarduous (to the motor) heat problems in the cores. But, like mentioned in my original posting, the base of at least the older blenders have inscriptions like: "115 volts 3 amps 25 to 60 cycle AC DC". Shouldn't that mean it will run fine on frequencies down to 25Hz? Maybe the older universal motors are sturdy, accepting machines... like a multifuel combustion engine? :)

Nice as it would be to have the blender modified internally, there are still affordable transformers like this one ($19.99):

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If the issue with frequency is not so great then this would be a realistic option. But yes, i sort of planned to sell on some of them (at cost price) to friends and family and... at 13lbs the transformer actually weights slightly more than the blender itself :)

Well, thanks for the help everyone! And if someone get a bright idea for motor modification i'd of course love to hear about it!

Kristian

PS. If it is of any importance we're talking very short running periods for the motors here! I don't think i've ever had a blender run for more than a minute continuously...

Reply to
kristian

I bet you will find a blender uses a "universal" AC/DC motor that doesn't care about frequency. I haven't really looked inside but usually that is what they use in high torque applications like this

Reply to
Greg

If the blenders are truly rated at 115V 25-60 cycles, then one could assume that they would also work at 50 Hz, in which case, all you would need is a step down transformer from 230 V. to 115 volts rated at about 500 watts or greater. (with some margin of safety) (3A x

115V = 345 VA).

I've seen plug-in Euro US transformers rated up to 1500 watts or so. These are big, heavy, and expensive. Your costs should be less as these are fairly common in sizes smaller than that. (Check appliance stores in large cities that sell European appliances). Perhaps someone else can recommend some web sources for these as well.

Transformers only convert voltage, not frequency. If you want to convert frequency from say 50 hz to 60 hz, Theoretically, You can do this with a modified UPS (Uninterruptible power supply ). The incoming source voltage (230 or 115 volts) is stepped down and rectified to DC at (typically) 12 or 24 volts and is used to charge a battery. The battery has an inverter connected to it and gives you the output at whatever the rated voltage and frequency is (230 VAC 50 Hz or 115 VAC 60 Hz). The modifications may be required because many UPS's have a relay that connects the output to the input voltage and the battery is left on standby charge. (during normal operation). This is not what you want. Any modifications can be dangerous if not performed by a qualified and knowlegable person. Just be aware of what you are getting into if you attempt this route.

Of course, if your specs are accurate, and these blenders will run on

25-60 Hz, the transformer solution is going to be a lot cheaper than the UPS solution.
Reply to
Beachcomber

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