EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: Mike09 on May 22, 2020, 08:17:26 pm
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Hi everyone,
I hope you can help me with this, or that there is a budget friendly solution for my issue.
I moved from Europe to Canada and took my trusted Personal Blender with me. Its only rated for 230v but still works on 110v half decently (didn't die so far).
Is there any way to convert the blender so that it works properly with 110v or swap the motor? I can solder and have a multimeter and other basic tools.
It would be great if there is a way to do that so that I don't need to buy a new blender.
Please let me know if you need any further information from me.
Thanks,
Michael
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Yeah, depending on how many watts you can buy an inexpensive adapter. Just search Amazon or whatever.
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I assume it uses a universal motor like most consumer market blenders do. (Some professional blenders use inverter drive motors, but I'm pretty sure trying to run one of those on half voltage will cause an error and not let it work at all.) Universal motors will also run on DC, so rectify AC to get 170V DC - you can easily find the bridge rectifier, NTC inrush limiter, and capacitors in a discarded PC power supply. Combine that with inductance no longer being a factor and it should get pretty close to the original 240V performance. Beware the original switch isn't designed for DC so use it to switch the AC going into the bridge rectifier.
There's also a trick of building an inverter to create another 120V waveform out of phase with the existing one, for a total of 240V, but that's a bit fancy for just one simple appliance. Might be worth considering if you have a lot of devices that need 240V.
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Mike09,
Welcome to the forum!!
(Welcome to Canada!!)
You actually may (edited after reading other comments) have 230V available in your kitchen:
(https://www.eevblog.com/forum/index.php?action=dlattach;topic=240210.0;attach=984242;image)
(https://www.eevblog.com/forum/index.php?action=dlattach;topic=240210.0;attach=984238;image)
The mains supply in Canada is actually
115 - 0 - 115
In the kitchen, and only in the kitchen, the two sockets are wired to two phases.
The is a socket designed for this:
[attachimg=1]
The pins are sideways instead of vertical.
Consult with an electrician.
Regards,
Jay_Diddy_B
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It may be there but it's not guaranteed. It was good practice in the 90s/early 2000s but as the GFCI requirements increased and copper got expensive it was much cheaper to install 120v 20A GFCIs and downstream protected outlets. (The normal GFCI outlets you get here cannot be split for 240v and GFCI breakers are expensive and inconvenient.) Before the 90s the use of a split plug was a bit rare.
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It may be there but it's not guaranteed. It was good practice in the 90s/early 2000s but as the GFCI requirements increased and copper got expensive it was much cheaper to install 120v 20A GFCIs and downstream protected outlets. (The normal GFCI outlets you get here cannot be split for 240v and GFCI breakers are expensive and inconvenient.) Before the 90s the use of a split plug was a bit rare.
The split 120/240V circuit does save copper compared to two separate 120V circuits - ground + neutral + 2 hots for a total of 4 instead of a total of 6 with separate circuits. It is still possible to use 120V GFCIs with such an arrangement by branching the split circuit into two 120V circuits, with two separate GFCIs. If the kitchen is a significant distance from the breaker box, the savings is often still worthwhile.
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Hi,
You might be able to tell by looking at the electrical panel.
The breakers may be labeled (Mine aren't)
[attachimg=1]
There will be ganged breakers for (If you have them):
Stove (cooker in the uk)
Air conditioning
Clothes Dryer
Etc..
These are 230V loads.
If you see ganged breakers for the kitchen you have split phase wiring in the kitchen sockets.
Regards,
Jay_Diddy_B
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Not necessarily. I don't recall what code says about that particular application but I know that I've seen kitchen receptacles wired that way without ganged breakers. I can't think of a reason you'd want to gang the breakers in a situation where you have a shared neutral, if one side is overloaded and trips the breaker there's no reason to have the sister breaker trip when they're feeding separate loads. Any circuit supplying a single 240V load will have ganged breakers because you don't want to have one breaker trip yet still have live wiring in the appliance relative to ground.
At any rate a 240V universal motor will not be harmed by running it from 120V although the power will be a bit lower. As was already mentioned, rectifying and filtering will get you 170VDC which combined with the fact that these motors produce a bit more power on DC vs AC ought to get you pretty close. Or you could build a doubler with a pair capacitors and diodes.
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Hi,
One reason for ganging them would be safety. If some unsuspecting homeowner thought they had turned the power off at the breaker only to leave half the sockets live.
There is a nice discussion on kitchen wiring here:
https://www.electriciantalk.com/f31/does-anyone-still-install-15a-splits-kitchens-26679/ (https://www.electriciantalk.com/f31/does-anyone-still-install-15a-splits-kitchens-26679/)
Jay_Diddy_B
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And then there's the sledgehammer approach of dragging out the 2000 VA universal transformer...
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How about fusing? I'd be concerned that 240V sockets won't have sufficient over-current protection for a device with relatively thin cable. Additional fusing maybe necessary.
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How about fusing? I'd be concerned that 240V sockets won't have sufficient over-current protection for a device with relatively thin cable. Additional fusing maybe necessary.
They'll be 30, 40 or 50A in most cases, so yeah, if you tap off of one of those you'll want to have a fuse as part of your adapter.
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Thanks for all the help! I will take a look at my wiring at home and will talk to a electrician.
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A commercial boost transformer that you can set on the counter is going to be a lot cheaper than an electrician. The blender is probably around 700W but given that they typically have a very low duty cycle, even a 500VA converter would probably work. I have one that I have occasionally loaded as high as 1kW for a few minutes without problems.
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Cooktops, dryers and ACs use 240V. North American domestic power inputs are 120V+120V two phase systems, with 120V+neutral entering wall sockets, and 120V+120V entering high powered devices.
If you can jerry rig (not a good idea though) your cooktop wiring, you can get 240V readily available from your kitchen.
Correction, 120V+120V split-phase. It’s just a single 240V phase with a center tap.
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Correction, 120V+120V split-phase. It’s just a single 240V phase with a center tap.
Exactly right. Two-phase power has not been common for the last century (wasn't it the system favored by Tesla?)
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There's also the "2/3" 120/208V system that's common in apartments and condos in the city, but not individual houses. It's more or less the 120/208 3 phase system wired such that every housing unit gets 2 of the 3 phases.
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A long time ago, when I was a teenager and moved to US, I converted some 220V appliances by unwinding some turns from the motors. You need roughly 3/4 of the turns to make the inductance go down.
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Correction, 120V+120V split-phase. It’s just a single 240V phase with a center tap.
I did mean 120V+120V separated by 180 degrees. Otherwise I would have said 2 out of 3 phases.
And that’s still wrong: in the US split-phase system, the two 120V halves are in phase.
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And that’s still wrong: in the US split-phase system, the two 120V halves are in phase.
It depends on how you measure. In terms of RMS or power supplied, they are in phase, but when graphed on the same axis they appear to be shifted by π radians. But historically "two-phase" meant a shift of π/2, and this is not that.
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And that’s still wrong: in the US split-phase system, the two 120V halves are in phase.
It depends on how you measure. In terms of RMS or power supplied, they are in phase, but when graphed on the same axis they appear to be shifted by π radians. But historically "two-phase" meant a shift of π/2, and this is not that.
with multiple phases you can generate additional phases with linear combinations of the phases
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And that’s still wrong: in the US split-phase system, the two 120V halves are in phase.
It depends on how you measure. In terms of RMS or power supplied, they are in phase, but when graphed on the same axis they appear to be shifted by π radians. But historically "two-phase" meant a shift of π/2, and this is not that.
Thanks for the added clarification!