Soft Start for 1/2hp shallow well pump.

Hairfarm
Hairfarm Solar Expert Posts: 225 ✭✭✭
in Off Grid Solar & Battery Systems #1
I found this unit that should fit the specs for my 1/2hp shallow well pump. My pump uses 9.5AAC @ 115ac.

I found this soft-start device from Schneider Electric:

Attachment not found.Attachment not found.

I'm anticipating a surge issue with my pump / inverter combo and was wondering if anyone has used a soft-start like the one pictured. It's around $200.

I'd like to keep my 1/2hp pump since it can fill an 80gal (30gal water) PT in around 5 minutes.
· Share on Twitter

Comments

  • smatthew
    smatthew Registered Users Posts: 15 ✭
    #2
    Re: Soft Start for 1/2hp shallow well pump.

    Is your well pump a three phase pump? 'because that's a 220v 3 phase soft-starter....

    edit: i see it does 220v 3phase and 120v 1phase. Interesting... Also check out the "Sure-Start". There was a thread on them here recently....
    · Share on Twitter
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #3
    Re: Soft Start for 1/2hp shallow well pump.
    Hairfarm wrote: »

    I'm anticipating a surge issue with my (1/2 hp) pump.
    I'm assuming this is an off the shelf jet pump. If this is so, surge will be a problem. A problem if the motor is of the capacitor start type, but a HUGE problem if it's not.
    30 gal of water in 5 minutes translates to 360 gal per hour. Too bad the old style piston pumps no longer are being made. My almost 60 year old piston pump is driven by a 1/4 hp cap start motor, pumps 360 Imperial gal per hour and draws an average of 300 watts while running. My 1000 watt inverter has no problem starting it.
    My uncle on the other hand has replaced his roughly 50 year old Duro 1/6 hp piston pump with a non-cap-start 1/2 hp jet and now his 2500 watt generator can't start his pump when the grid goes down. The old "DURO" 1/6 hp piston supplied 250 imperial gal per hour at it's designed operating speed. Duro stopped making them about 20 years ago when the retail price had to go to $1000 Cdn. Here's a video of a rebuilt Duro with it's original motor replaced by a 24 volt DC motor: http://www.youtube.com/watch?v=smo9dDXysIM
    In the video the guy is using a motor pulley bigger than it should be, thus driving the pump faster than designed. One of the results is overloading the motor and stalling it out by the time pressure reaches 90 PSI. Otherwise it would have no problems reaching over 100 PSI and really blowing off the pressure relief valve. These were amazing pumps and there are likely many used ones out there ready to be picked up and rebuilt. I have my grandfathers, complete with it's original Wagner Electric, capacitor start 1/6 hp motor, (he died in 1957) rebuilt and on standby in case I ever need to put it back in service. Later ones came with a standard 1/4 hp motor, way bigger than needed, but cheaper.
    · Share on Twitter
  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    #4
    Re: Soft Start for 1/2hp shallow well pump.

    I was looking at piston pumps for a direct panels to pump situation but I was concerned about the pulsed nature of the load. Ie, I imagine that the torque and therefor current draw isn't very steady. But wouldn't be a problem if there is a battery (or perhaps ultracapacitors) to buffer it.

    A 3 phase motor can be used with an VFD to address start-up surge, but most of them require a 240VAC supply. There are also a number of ways to reduce single phase motor start-up surge (see other threads).

    I am available for custom hardware/firmware development

    · Share on Twitter
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #5
    Re: Soft Start for 1/2hp shallow well pump.
    jonr wrote: »
    I was looking at piston pumps for a direct panels to pump situation but I was concerned about the pulsed nature of the load. Ie, I imagine that the torque and therefor current draw isn't very steady.

    True, there is a cycling change in current draw as the piston does it's work, but it's not sudden as in switched, rather it relatively slowly increases and decreases and shouldn't be a problem for the battery unless it's undersized. It the battery can't handle the pump in normal operation, it would never get it started in the first place. Plus,the inertia of the motor rotor helps smooth things out. The load on battery is sort of like going from low beam to high beam with your cars headlights, except unlike the headlights, there are no spikes etc.
    · Share on Twitter

Categories