motor start stop

[mengbly]

Hello everbody

can anyone please help me in answering the below questions

1. what is the logic behind number of start/stops for domestic water pumps, is there any formula or calculations for the same ?

2. How to calculate the expansion tank size for the booster pumps, is the tanks size also related to the number of starts and stops of the pump??

thanks

 

[waross]

The number of starts allowed per hour is to prevent overheating from starting current.
The size of the expansion tank may be related to the time between starts or it may be related to the volume of the system and the increased volume due to temperature rise.
It depends.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[electricpete]

To help estimate starting limits, take a look at:
faq237-1285


Bill has it right about the reason for starting limits.
He also has it right that relationship between expected starting frequency and tank size (if any) depends on the system.

A note about terminology, in my limited experience a tank called an "expansion tank" would not be related to motor start frequency. A tank called an "accumulator tank" would be related to motor start frequency. But don't focus too much on the terminology, look at the system and how it's operated.


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(2B)+(2B)' ?

 

[itsmoked]

Absolutely the expansion tank is related to the start-stop cycle count. The larger the tank the less starts and stops and the greater the period between them. Going small (cheap) is a way to make it cheap by differing cost to short-lifing the motor.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

Expansion tanks are often found on hydronic heating systems to accommodate thermal expansion of the water.
The tanks used for storage and or pressure are often called pressure tanks or storage tanks.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[electricpete]

itsmoked - There are clearly some tanks that affect start/stop duty and some that don't, depending onthe role of the tank within the system. My point was that to the limited extent the name gives us a clue about the role of the tank, an expansion tank falls in latter category.

http://en.wikipedia.org/wiki/Expansion_tank

and an "accumulator" falls in the former category

http://en.wikipedia.org/wiki/Hydraulic_accumulator

Your "absolutely" comment makes an assumption contrary to the above terminology. I think we'd both agree the function of the tank is more relevant than the name.


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(2B)+(2B)' ?

 

[MikeHalloran]

Mengbly,
you have so far started three separate discussions with the exact same question.

Please go to the other two, Red Flag them, and in the resulting dialog box, ask that the discussions be removed.

Please do not multiple post again.
Thank you.



Mike Halloran
Pembroke Pines, FL, USA

 

[DRWeig]

Yes, mengbly -- what MikeHalloran says.

Please read the forum policies. There's a link below my name.

Best to you,

Goober Dave

Haven't see the forum policies? Do so now: Forum Policies

 

[mengbly]

Dear All

Thanks for the reply and my apology for posting in three forums
i am gonna remove them now

regards

 

[itsmoked]

Agree all: "Expansion" tanks do not have anything to do with cycling times in water systems but rather pressure tanks, or bladder tanks certainly do. I took the OPs question to be about pressure tanks. I should'a made that more clear..

Keith Cress
kcress -

http://www.flaminsystems.com