Old Welch 1400 reassembly

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Posts: 11
Joined: Sun Jun 12, 2016 11:10 pm
Real name: Filippo Passeri
Location: Czech Republic

Old Welch 1400 reassembly

Post by Filippo_Passeri » Thu Oct 26, 2017 8:05 pm

Hello, all.

Recently I have been accumulating parts for my Welch (probably 1400) head to rebuild it. I have everything except the smaller pulley for the motor. I'm planning to lathe the previous pulley to a smaller diameter to fit the RPM rating of the pump.
The motor rating is 500W and 1430 RPM (although I measured it without load to be close to 1500 RMP).

It's written on the pump head that the optimal RPM is from 400 to 475. From rough calculations, the necessary ratio for the Vacuum pump pulley to the motor pulley is 3.5:1. So I need to reduce the previous pulley to 50mm to achieve optimal RPM.

Any suggestions or corrections?
View from the side
IMAG0203 (1).jpg
The smaller motor pulley to be lathed
View from top
"Will you remember the famous men who have to fall and then to rise again,
So take a deep breath, pick yourself up, dust yourself off, and start all over again."

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Richard Hull
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Joined: Fri Jun 15, 2001 1:44 pm
Real name: Richard Hull

Re: Old Welch 1400 reassembly

Post by Richard Hull » Sat Oct 28, 2017 7:47 am

All Welch belt drives are slow winders. This gives them their long life reputation and quiet drive noise. You can go to sleep listening to that quiet lub-lub-lub, just like the railroad track joints click-click putting you to sleep in an old Pullman sleeper car.

Good luck on getting the pump going.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Dennis P Brown
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Joined: Sun May 20, 2012 2:46 pm
Real name: Dennis P Brown
Location: Glen Arm, MD

Re: Old Welch 1400 reassembly

Post by Dennis P Brown » Sat Oct 28, 2017 6:44 pm

Those are really great pumps that will give you many years of excellent service. I love their internal simplicity - they are so easy to open and then clean!

Really nice how you are partly rebuilding it and making the system "like - new" again. I prefer the belt drives (with a safety cage installed) since it makes service easier compared to current single piece systems - when the motor goes on these newer type pumps, only that exact motor type can be used.

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