KitchenAid Wash Arm RPM

[labboy]

So I was looking thorough some old KitchenAid (Hobart) Service Manuals. I saw that there was a specification for RPMs for the wash arm.

How was this measured when in the field?

Curious,

Bob

 

[funktionalart]

I'm curious about...

both, actually. How they tested it and what the result is. labboy, what is the rating, anyway?

 

[stevet]

not rocket science!

Take a small wire or thin metal hanger and put it thru a rack so the arm just nicks it as it turns and count how many times it hits the arms in a minute and then divide the number by 4 to get your rpms. About as close as you can get to it!

 

[tomturbomatic]

You could hear it for one thing, both with the Big Blue Wash Arm and the 4 Way Hydrosweep because the Hydrosweep had one tube with an angled jet at the end and it made a distinctive sound each time it passed the door. I think I remember the literature with our 15 stating that the arm turned at around 47rpm. The BBWA spun much faster, with the owner's manual for the 14 stating that, "A wall of water revolving at more than 100 revolutions per minute cleans every dish with an up and down scrubbing action." The booklet from the KD-11 states that the arm turns at approximately 60 revolutions per minute. That's once a second!

Most of you are too young to remember or have noticed, but in 1970, there was a television ad for Palmolive dishwasher detergent extolling its ability to keep down protein foam in the wash water. They had a 14 or older KA dw with a glass door with a port through which they could add detergent (shades of Robert). It was empty to better show the water. On top of it they mounted a light bulb with a switch activated by the pressure from the endmost jet in the Big Blue Wash Arm. They started it washing and the light flashed every time the arm made a revolution. Gradually, the foam built and the wash arm slowed. They pointed this out and then added the Palmolive which killed the sudsing making the arm turn faster and the light flash more frequently. It was one of the most fascinating TV commercials in a long time because by this time appliances were no longer shown operating on TV.

 

[electronicontrl]

no youtube?

That would be one fun commercial to see. I may have seen it but do not recall it.
I do remember the "Old Lonely" commercials, though.

 

[murando531]

The way I've tested this is to put a big spatula or something to block the arm that you're not testing, and then put big bowls in the lower rack in such a way that the end jets of the arm can still hit the door. Then just run and listen to the rate that the jets sweep the door and the corners of the door. Depending on what parts of the arm have jets at the very end, you may have to divide by that number, for example if the arm has end-jets on opposing ends, you'd divide the rate of the sound by 2. If you heard a swish every second, you'd know that the arm is actually rotating once every 2 seconds, so that'd be around 30 RPM.

100 RPM actually seems like it would be quite fast, especially for the jets to be coming from 4 arms instead of 2. But with the volume and pressure coming out I'm sure it didn't affect performance at all versus the arm moving slower. I've always thought the common speed for an arm to be around 30-45 RPM. Even 60 seems a bit swift.

 

[murando531]

If you can get your hands on a GoPro, and put a flash light in a sealed Ziploc, that's the fool-proof way of telling exactly what's going on in your machine. That's how I found out my upper arm was sticking.

 

[tomturbomatic]

There was never 100 RPM. The Big Blue Wash Arm revolved at 60 RPM. The misleading statement from the manual for the 14 series stated that the wall of water from the BBWA revolved 100 times a minute which would, I guess, be a possible way of stating it if you counted both sides of the arm or something. It was certainly a more powerful and faster moving wall of water than in that new machine that advertises a wall of water.

The 4 Way Hydrosweep revolved at about 47 RPM, if I remember correctly from our owner's manual.