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Old 26th Mar 2017, 4:04 pm   #21
Mike Phelan
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Default Re: Kenwood Chef A701a motor

That looks like excessive sparking. With the brushes out and the gearbox out the armature should spin freely.
If they are sintered bronze bushes for motor bearings thin oil ought to free them.

Sorry for being vague but it's a few decades ago since we had a Kenwood A701!
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Old 29th Mar 2017, 9:00 pm   #22
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Default Re: Kenwood Chef A701a motor

Ok I've just relived the motor and given it a bit of a service, and have noticed that the burning smell is from the large resistor. It smokes! It's new though.. what can cause that?
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Old 30th Mar 2017, 12:07 am   #23
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Default Re: Kenwood Chef A701a motor

Probably just residual oil/grease contamination burning off at normal operating temperature, though it could be overheating.
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Old 30th Mar 2017, 7:02 am   #24
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Default Re: Kenwood Chef A701a motor

But surely not it the resistor has only recently been replaced? It's clearly overheating, I can see the green ceramic on the resistor blackening as it gets hot and then it smoked
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Old 30th Mar 2017, 7:05 am   #25
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Default Re: Kenwood Chef A701a motor

Here's a thought! Could it be that the minimum speed is too low, making the resistor work harder?
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Old 30th Mar 2017, 2:10 pm   #26
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Default Re: Kenwood Chef A701a motor

I think you have a shorted winding on the armature. This is causing excessive current to be drawn - the sparking and hot resistor are the consequence.

Look out for a new motor or armature, there's loads of spares on ebay

http://www.ebay.co.uk/itm/Motor-For-...8AAOSw4shX4tVK

http://www.ebay.co.uk/itm/Kenwood-Ch...EAAOSw9N1VppAT

http://www.ebay.co.uk/itm/Motor-For-...EAAOSwopRYlbuz

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Last edited by fetteler; 30th Mar 2017 at 2:13 pm. Reason: links to parts
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Old 30th Mar 2017, 3:12 pm   #27
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Default Re: Kenwood Chef A701a motor

Oh dear, I was really hoping that wouldn't be the case, but that is clearly the issue... do you know how a winding gets shorted out?
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Old 15th Apr 2017, 10:30 pm   #28
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Default Re: Kenwood Chef A701a motor

I have now bought a new motor from a spares or repairs kenwood but it's still sparking the same amount and making the resistor hot. Would it deffonately be a faulty winding? Is it common for them to develop shorts?
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Old 16th Apr 2017, 3:01 am   #29
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Default Re: Kenwood Chef A701a motor

Does the resistor go in series with the motor at low speed being linked out by the control as speed and load increases.
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Old 16th Apr 2017, 3:20 pm   #30
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Default Re: Kenwood Chef A701a motor

Unfortunately I'm not certain. I can't find a service manual or diagram anywhere to check other than this unofficial one: https://hyperentang.wordpress.com/
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Old 16th Apr 2017, 3:37 pm   #31
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Default Re: Kenwood Chef A701a motor

I've been looking into causes, and people keep saying it's the components at fault. I can't see it though as I have replaced them all. Could they be duff components? The resistor tests OK.
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Old 16th Apr 2017, 4:26 pm   #32
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Default Re: Kenwood Chef A701a motor

I haven't fixed one for a long time but seem to remember that the armature brushes sparks a lot and so the does the governor contacts. Not sure about the latest type but the early method of speed control was crude, with little or no filtering. I used to bed in the carbon brushes. Don't remember a resistor getting hot though. Have you looked on youtube, there must be one on fixing a food mixer.
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Old 17th Apr 2017, 11:32 pm   #33
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Default Re: Kenwood Chef A701a motor

Hi yeah I tried to do that but no one seems to be posting videos on this specific issue. I have taken off the Bakelite bit at the bottom which sets the minimum speed.. perhaps it's too fast? I didn't really pay too much attention to how much the screws should be done up. Does anyone know how much the rpm should be for the high speed outlet?
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Old 23rd Apr 2017, 2:24 pm   #34
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Default Re: Kenwood Chef A701a motor

Hi guys, just a quick update. I've discovered that the smoking was due to the resistor I got in the kit. I don't know what its made of but I replaced it with the original which was working ok and it seems to get hot as I expect but with no smoke. So that's ok. I also changed the armature winding. However I now have another issue. On its side, the motor was going fine, but when standing it pulses on low speeds... not sure why this is?

also its not the carbon brushes, these are new...
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Old 23rd Apr 2017, 2:46 pm   #35
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Default Re: Kenwood Chef A701a motor

They do pulse at low speed without any load.
 
Old 23rd Apr 2017, 3:55 pm   #36
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Default Re: Kenwood Chef A701a motor

Really? It never used to. Perhaps that was originally due to the capacitor failing?
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Old 23rd Apr 2017, 4:02 pm   #37
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Default Re: Kenwood Chef A701a motor

A little bit of pulsing is normal when the low speed screws are set correctly.
They usually drift high in use and the screws can be adjusted with the covers on.
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Old 23rd Apr 2017, 4:10 pm   #38
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Default Re: Kenwood Chef A701a motor

That's no load, not even the gearbox.
 
Old 23rd Apr 2017, 11:41 pm   #39
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Default Re: Kenwood Chef A701a motor

Thanks guys! I have posted this video of the final article. Please do pay attention to the sound though and confirm it's normal as it's more than a little pulsing, and also the gearbox is engaged.

Anyways I have the case a polish too after and it looks great!!

http://https://youtu.be/WNwsffjdduE
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Old 24th Apr 2017, 2:56 am   #40
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Default Re: Kenwood Chef A701a motor

The video does not play so the link might need to be looked at.
Have you still got the dust cover for yours?
We have still got the dust cover for ours.
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