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I'm looking for a backup power solution for my catchment system. I tried my 2500w (5000 peak) inverter today and it wouldn't power the pump. So I need another option. It's a Grundfos GPS4-A pump which is pretty standard around here.
The details on the pump plate is here:
http://www.e-z-caps.com/images/GRUNDFOS%20PUMP.jpg
The brochure for the pump is here:
http://www.tppump.com/media/literature/B...ochure.pdf
Basically my question is, what size generator do I need to make the pump run?
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Manual says peak ~1.6KW, but the inrush on a dry coil can run up to 10x the working load, especially when modified sine power is involved.
Suggest minimum 5KW generator; while a smaller one (say, 3750W) might work, you're left with no headroom.
This is also a big enough load that (1) a lossy wiring run can be problematic (2) wiring for 220 is a clear win (in which case a 5KW is usually the smallest generator with a 220 tap).
Alternate solution: DC-powered backup pump. Possibly cheaper than a generator.
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Kalakoa is correct.
Or perhaps you can find a good deal on a used true sine 4kw-5kw inverter?
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I fixed my friend up with the same re-purposed SmartUPS 3000 that I installed for myself. It runs his catchment pump OK. This UPS inverter has a capacity of 2,700 watts (3,000 volt-amps) and is pure sine wave. His pump is 1/2 hp and is set up for 120 volts. Checking the obvious first, what voltage and HP is your pump? If you are trying to run a 220 volt pump on 110 it's not going to run well. When you say it wouldn't power the pump, what happens? Does the inverter trip off? Does the pump sit there and hum?
Some motors will run on modified sine wave but will draw more current. Given that my friend's pump runs OK on a 2,700 watt inverter I would suspect the problem is due to a MSW inverter rather than too small an inverter. Course if you already have a TSW inverter then I am obviously wrong.
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Conversion factor: 1HP = 750W. (Not sure why the Grundfos specs are double this, unless they're counting peak inrush.)
A 3KVA inverter leaves plenty of headroom for 1/2HP of pump motor. (Side note: I've installed plenty of APC, as I recall they're all MSW except for the Matrix line.)
Most larger motors have split windings that can be wired in either a 110 or 220 configuration. I've seen at least one installation where rewiring for 220 "fixed" other problems.
Grundfos claims ~13A peak for their 1HP, this is very close to the code limit for 14ga (15A) and leaves little headroom for the 12ga limit (20A). If the run is more than about 50 feet, upgrading to 10ga (or switching to 220) will probably help.
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quote:
Originally posted by MarkP
I fixed my friend up with the same re-purposed SmartUPS 3000 that I installed for myself. It runs his catchment pump OK. This UPS inverter has a capacity of 2,700 watts (3,000 volt-amps) and is pure sine wave. His pump is 1/2 hp and is set up for 120 volts. Checking the obvious first, what voltage and HP is your pump? If you are trying to run a 220 volt pump on 110 it's not going to run well. When you say it wouldn't power the pump, what happens? Does the inverter trip off? Does the pump sit there and hum?
Some motors will run on modified sine wave but will draw more current. Given that my friend's pump runs OK on a 2,700 watt inverter I would suspect the problem is due to a MSW inverter rather than too small an inverter. Course if you already have a TSW inverter then I am obviously wrong.
It's a 1 HP pump and according to the stats it can be run either 120 or 220 volt (ours is setup for 120). It is a modified sine wave inverter. When I try to run it the inverter and the pump cycle on and off which is what these inverters are supposed to do when they are overwhelmed. The cycle is quick so the pump never gets over it's required starting load.
I did initially suspect the inverter, but I have two of them and they both behave the same way, not to mention that just one of them can run a full size fridge, TV, DVD, lights, and everything else in the house with no problem. When the pump kicks on under normal use it does cause the lights in the house to flicker.
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quote:
I did initially suspect the inverter, but I have two of them and they both behave the same way, not to mention that just one of them can run a full size fridge, TV, DVD, lights, and everything else in the house with no problem. When the pump kicks on under normal use it does cause the lights in the house to flicker.
Fridge compressor is usually something like 0.125 HP.
If the pump startup dims the lights, that's probably a wiring loss issue -- as the voltage sags, amperage increases to maintain the same relative "power". Last time I saw this, rewiring for 220 fixed the problem.
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I have a Honda eu2000i. It's a great little generator that puts out not pure sine wave but close enough to fool anything that asks. It is rated at 1.6 kw continuous/2kw surge. It only puts out 120 volts, no 220. Sounds like the only benefit it might have over your present inverter is the virtual true sine wave. If you could borrow one to try it that might answer some questions. All that being said, I have a "spare" Generac 3500XL (4kw surge). It is the old standard iron generator without any fancy electronics. When the pump starts the genny will slow down and meet it half way. It also puts out 220 volts. Interested in taking it off my hands? Could borrow the eu2000i for that matter too. Where are you?
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We have the Grundfos JPS4-A pump (1 hp, 115v) and have run it on a Honda 3000i for a couple of years now. The Honda will dip when the pump kicks on, but even on their Ecothrottle it has never overloaded.
