How much generator for a vacuum pump

[Anonymous-0]

How much generator will I need to run a 230 volt, 21 amp, 4 1/2 hp motor on a Surge Alamo vacuum pump. I know it will draw just shy of 5000 watts running, but how much will it take to get that motor started? Will a 10,000 watter do it?

 

[buickanddeere]

Depends...........a 10KW might if PTO driven . A 10kW -18HP portable gasser probably not. Assuming is a rotary twin screw pump or a vane pump? There has to be other electrical loads to run as well? Is there a proper transfer switch? Around here a 20-25KW pto gen goes for under $2000

 

[Anonymous-0]

Gas engine, vane pump. dedicated use, no other power draw. The more I research it's looking like 15K minimum. I wonder if a 2 hp motor would run the vacuum pump with 2 surge milkers on it?

 

[John T]

Not knowing the starting characteristics of pump nor the surge rating of the generator we can only hazard an educated guess, but my best uninformed "gess is a 10 KW will do the trick. If it has any decent surge rating and the pump is unloaded for start up I believe a 10 KW will get it started while the running wattage is considerably less which shouldnt be any problem...

John T

 

[RodinNS]

Depends.... a LOT. I'm going to guess and say it's an Alamo 75 plus... so that should be a belt driven vane pump. You might start that on 10 kva. If it's a direct drive pump with the 1200 rpm motor... I think you're probably going to NEED at least 15 KVA.
That's based more on observation that pure electrical theory.
Neighbours have a 5 hp direct and a 15 kva Magnate MKII gen.... and I think they need to give the pump shaft some 'help' to get started.

Rod

 

[kris Jensen]

you are probably in the right range. Is it for a backup in case of power outage?
Seems like ages ago when I farmed we had two surge units and ran them off a stall cock on the manifold of the tractor when the power went out. only happened a couple of times but a valve(stall cock) on the tractor and some hose to one in the barn had us going, and it would operate two milkers

 

[Anonymous-0]

Are you sure you mean KVA? I toured a co-gen air separtion plant that also powered a large refinery. It had enough power for 25,000 homes and the name plate said 96 KVA. It was powered by a 25,000 HP turbine and produced 138,000 volts. 15 KVA seems like a pretty big generator. They had a big back up generator at this plant but I didn't see the name plate. It was a 3412 Cat engine though. Might have been 25 KVA?

 

[JMS/.MN]

I don"t doubt that a bit. I"ve had a WinPower 25/45 since the late 70s on the dairy. Ran the 10 hp vacuum pump plus other peripheral motors like the bulk tank. (5 hp and fans, water pump, sometimes house heat, etc.) Didn"t run the 10 hp manure pump at the same time.

 

[John T]

Good point, the KW = KVA ONLY if the Power Factor is unity.......and with heavy inductive loads (like say a motor) thats NOT the case...

John T

 

[RodinNS]

As John has said, 1 KVA = 1KW at unity. Some gens are rated in KVA; some in KW. I'd really have to go back and brush up on my power factor stuff to say how close the two are in practice...
As far as the 3412.... that's enough engine for probably 600+ KVA depending on the application.
Your typical backup PTO generators run between 15 KVA and 50 KVA...

Rod

 

[Anonymous-0]

Just looked and it's 96 Mega watts on the name plate but was rated at 80 because it only reaches peak power at cold temperatures since it's turbine powered. Excess power is sold to the Alberta power grid.

 

[RodinNS]

Could be... but 96 MW is quite a large plant for a turbine. NSP runs a series of turbines here for backup power in the even they have a problem at a thermal plant and can't buy it in off the grid at a reasonable rate... but I thought those were more in the range of 25 MW units.
That 25 MW unit alone would require 38-40000 hp.... not factoring in any friction losses in the drive. In reality it's probably more like 50000 hp to drive the 25 MW plant... Did they have multiple turbines driving the 96 MW unit?

Rod

 

[buickanddeere]

How many KW generator to reliably start the 4.5HP vacuum pump without burning out the motor or generator. ???

 

[buickanddeere]

How many KW generator to reliably start the 4.5HP vacuum pump without burning out the motor or generator. ???

 

[Anonymous-0]

I looked at a website for the plant and it said 80 mega watts but I'm almost sure the nameplate said KVA. I even asked the guy giving the tour and I thought he said it's the same thing. I remember it being a 25,000 HP natural gas turbine and they use the exhaust to create steam to sell to the refinery. The refinery produced CO2 which was piped back to the plant and after being filtering and purified was resold to other customers. It was a win/win situation for both companies. The CO2 would normally just have been released to the atmosphere. I also looked and see that this plant only powered an upgrader for the refinery and another big generator powered the main refinery. The plant sold 700 to 900 tons of oxygen per day to the refinery and I think something like 2000 tons of steam but can't remember for sure. Maybe I got my numbers wrong and it's a 250,000 HP turbine? The plant cost $150,000,000 to build.

 

[sammydwm]

we used to use a 15KW generator when we had a 5HP vacuum pump. Even then the old 720 would snort when we started up.