Detail design of solar water pumping

kcbibek310kcbibek310 Registered Users Posts: 12 ✭✭
Can anyone help me to give idea about selecting suitable VFD controller in solar water pumping( 3-phase Submersible pump). And also calculating the size of wire from VFD device to pump. 

Comments

  • mike95490mike95490 Solar Expert Posts: 7,249 ✭✭✭✭
    We need to know the size (HP) of the pump, and the voltage it runs at.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • kcbibek310kcbibek310 Registered Users Posts: 12 ✭✭
    Suppose the pump is of 3HP and the operating voltage is 415V and the distance between VFD( Controller/Panel) to pump is 100m( Length of cable)

  • mike95490mike95490 Solar Expert Posts: 7,249 ✭✭✭✭
    Ouch !  That's going to be expensive bag of parts.  Your VFD manual may have some suggested wire gauges for long runs, or they may caution against long runs,  going to have to read the manual
    Cheapest controller I can find, is about $900
    https://www.grainger.com/product/EATON-Variable-Frequency-Drive-32WP39
    Your mileage may vary

    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • kcbibek310kcbibek310 Registered Users Posts: 12 ✭✭
    Why it is problem with VFD if we have long cable?
  • mcgivormcgivor Registered Users Posts: 1,220 ✭✭✭✭
    Capacitance becomes an issue when long cables are between the drive and motor, this can be corrected with inductors, but the best solution is to keep the distance between the two as short as possible, the run to the drive is not as critical, so mount the drive at the pump end.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • kcbibek310kcbibek310 Registered Users Posts: 12 ✭✭
    But i think while selecting the cable length for any motor or pump, we mainly focus on the voltage drop in the cable., isn't it? And i think the value of capacitance can be neglected upto 100m. Can you tell me about it?
  • mcgivormcgivor Registered Users Posts: 1,220 ✭✭✭✭
    The distance between the drive and motor is to be kept as short as possible, naturally the conductors must be sized correctly to account for voltage drop, what you don't want is the drive feeding a motor 100 meters away, even with shielded conductors, it's a little hard to explain but read this link to gain insight. http://www.invertekdrives.com/variable-frequency-drives/problems-with-motors-and-cables-22.aspx
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • mcgivormcgivor Registered Users Posts: 1,220 ✭✭✭✭
    Another point worth considering is if the motor used is rated for use with a frequency drive, the windings must have an insulation rateing higher than the supply voltage, to account for spikes, in the case of 600V motors the insulation rating must be 1000V, premature failure will most likely occur if this is ignored.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • jonrjonr Solar Expert Posts: 846 ✭✭✭✭
    edited October 11 #10
    Rarely is it wise to operate right at the limit (100m).  I would locate the VFD (but not the panels) closer to the pump.    If you can't, then use a load reactor.

    I assume you are using an inverter to get a steady 415VAC?  That's a shame since the VFD is just rectifying it and then doing similar things.
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