Why Did Older Dishwasher Have Such Enormous Motors?

[Chetlaham]

I mean why were they so big considering modern dishwashers get dishes clean with a 50 watt motor?

 

Why not make a two port sump (think plastisol tubs) and add a removable find filter basket?  180 watt wash pump like this:

 

Pardon Our Interruption...

 

And a 25 watt drain pump like this but in shaded pole version:

 

Pardon Our Interruption...

 

Frog eye or cat eye spray arm with small holes. Continuous advancement timer (like on GE machines) where the drain pump starts and the wash motor shuts off 30 seconds latter. Similarly after the drain pump shuts off, fill starts and 30 seconds latter the wash pump comes on. 

 

I think this would have been cheaper, used less water and reduced carry over water found in many designs.

 

Why not have gone this route? Speed Queen could pull if off today if we wanted a no frill machine but also respected modern design. 

 

[rollermatic]

i'm of the old school

i have a lot of old dishwashers and the bigger the motor and the more water they use the better in my book! but i'm into them for the nostalgia of it. the old hobart kitchenaids had 1/2 hp motors, the gold seal motor they called it. i have a bunch of kitchenaids, over 20 and i have never had a problem with a motor yet! i've had lots of other issues, but not those powerful motors. hobart used to advertise them as lasting longer because the bigger motor would be under less stress.

and i think the rest of them used 1/3 hp motors, most of them 3450 rpm, but hotpoint used a 1/3 hp 1725 rpm on it's old machines, i have 2 of those plus one new extra motor. they used a big wash pump with a big water slinger impeller since their motors ran slower. but the g.e. mobile maids used a 3450 rpm 1/3 hp motor.

not sure what maytag and whirlpool used, although i do have a maytag front load in harvest gold from early 70's that has a horizontal pump and motor and it's gotta be at least 1/3 hp i would guess.

i would say back in the early days no one was concerned about energy usage and the idea was to build these machines to last which indeed they do or we would not have all these great 50 year old machines still working fine! and they had powerful pumps and used a lot more water because again no one was worried about water usage. these new machines i have no respect for, they drizzle a cup full of water around and take 2 hours to do a load, please! give me a water guzzling kitchenaid or frigidaire any day! but then i only run them for hobby so energy usage is not an issue. at least with me.

manufacturers definately believed bigger was better!

 

[qsd-dan]

Big motor + lots of hot steamy water + brute force + phosphates + bleach was how the dishes got cleaned in a timely manner.

Whirlpool Ultrawash/Power Clean dishwashers were still using a 1/3 HP motor through 2010. Detergent with phosphates and bleach were available through 2009, so it wasn't all that long ago.

 

[henene4]

1/3hp = 250W

More power usually means more water moved at higher pressure and/or speed.

Modern DW actually do the same often: Variable speed pumps often ramp up for intensive or quick cycles.

Efficiency is another matter:

While motors in general are relatively efficient, these motors more often than not were asynchronous motors - probably the "least efficient" of all of these.

Still pretty efficient (over 90% I'd guess) but not quite what today might be possible.

So you'd have to subtract that.

Efficiency of water path designs and pumps themselves were lower as well.

Fluid dynamics is a complicated and frustrating science.

Without computer simulation optimization was just not quite at the point we got to today.

Detergents just called for high mechanical action and large water quantities as well.

They weren't quite at todays standard, so more solvent (water) and more movement of that just forced things along.

And silence and efficiency just weren't jet asked for.

Getting the job done well was the first task.
Then they looked at makeing the machines cheaper.
Then efficiency came up.

Adding the lack of alternating spray (efficiency addition) and you could probably equate 100W today would be equivalent for 250W in a machine back then.

 

[kenwashesmonday]

As one one of the few who still uses a portable full-size dishwasher that get's parked in front of the sink, I appreciate a machine that finishes in a reasonable amount of time.  My 18 year old Maytag Jetclean portable runs for 51 minutes on 'light wash' and does a fine job.  I dread the day that I have to replace it.

 

[acesup8000]

1/2 Horsepower Motor

The KitchenAids from the 15 Series to the 21 Series used the 1/2 Horsepower motor that was made by Hobart. Once Whirlpool took over KitchenAid, I think they eventually made these dishwasher motors weaker.

 

[johnb300m]

I can verify that even when “evil” Whirlpool took over KA, they still had “gold seal” 1/2 hp motors up to the 23 series.
Only in the 24 series fully on the PC platform is when the motors went to 1/3hp.

 

[vacerator]

When they used to

really clean dishes well too! They cheapend the motors and pumps, and raised prices of course.

 

[combo52]

KA DW Horsepower

The KD10-14 machines had a 1/4 HP motor and the KD15-22 machines had a 1/2 HP motor.

 

Whirlpool did claim that the KD23 series had a 1/2 HP motor but it was the same size as the standard WP DW motor which was rated at 1/3 HP.

 

These large split phase motors were reliable but only about 30% efficient at best at converting power used to washing power.

 

John L.

 

[gelaundry4ever]

my thoughts

I believe that having a big motor equals power in every way, including spray and drain power. These are my thoughts.

 

[norgeway]

The 1725 Hotpoints

Worked ok, but were the all time noisiest dishwashers ever made.They sound like a garbage disposal fighting a chainsaw lol.

 

[maytag85]

Reply #10

Hans, wasn’t that the particular model you mentioned at the wash in back in 2019 you “wouldn’t miss more than an abscessed tooth” when I asked if you missed that particular model of dishwasher?

 

[volvoman]

@ Reply 4

This.

My wife and I have a portable Whirlpool that hooks up to the sink. I'd take a venture that it's close to 30 years old, if not more. It's loud. It uses a ton of water. And I guarantee you that it cleans better than anything currently on the market. It's not a Power Clean (it's actually kind of basic? Maybe an MOL?), but it'll blast the crud off anything you throw in there.

Contrast that to the fancy, HE-style dishwasher that we have in our timeshare, which takes HOURS to complete a load, and still leaves the dishes disgustingly wet.

We don't care about energy or water conservation. We want a machine that'll do the job well - and fast. We've already made the decision that if this one goes, we'll either find someone to re-build it, or we'll scour the classifieds for a used one.

 

[combo52]

Older, whirlpool, dishwasher

Hi Steve, what model were portable dishwasher do you have? They made several different styles over the years.

I have two 35-year-old whirlpool built-in whirlpools in my kitchen. I do have concerns about some of the aspects of the new machines they do get dishes very clean, however.

But I like the cycle times of the older ones in the fact that they will wash away so much food soil without ever ever having a filter to clean.

 

[launderess]

My vintage GE Mobile Maid has a giant whopping motor and can move water like no one's business. No wet wipe dishwashing here, machine actually will shimmy and slightly move about from force of water.

Sadly all that brute force has ruined no small amount of dish and glass ware so that's me for you.

 

[daveamkrayoguy]

Supposedly now, those smaller motors can do more, maybe with advanced technology doing more than we'd thought--or maybe they're strong to the finish 'cause they must eat lots o' spinach...!

 

 

 

-- Dave

 

[Chetlaham]

Reply 13

That pictures wells up a lot of emotion in me, including deep sadness and longing. I wish that PowerClean was still being made today. No other dishwasher comes close in the history of humanity. If everyone was like me that dishwasher would be in every kitchen across the globe and the heater wouldn't cut off after the thermal hold... Sadly when the tall tubs were introduced people began buying them and it only increased. Whirlpool was clever, they had the point voyager which kind of mimicked the power clean to help get a certain number people on board with the idea- as if nothing was missing- then quietly switched to the filter design. All around messed up. I dislike how passive and naive people are.

 

[qsd-dan]

Smaller motors don't do more work, they just run 6 times longer to get the same job done. Instead of 20-30 minutes during the wash and rinse cycles, it's 1-2+ hours. Between weak designed motors to save electrical costs and reduced water levels to save water, dishwashers are quickly heading towards alternating wash arms as being the norm. Probably expect longer cycles times from them in the future.

 

[combo52]

About 90% of dishwashers

Have been alternating wash arms for over a decade now, this practice fix the dishwasher quieter, allows it to have less water that has to be heated in the machine, and generally does an excellent job

By any measure newer dishwashers today get things cleaner than the older machines ever could that’s the advantage of a long cycle. It will soak things off and then scrub them off that older dishwasher couldn’t touch, except on the very long and energy intensive pots and pans cycles that a few machines had.

John