1hp well relay advice

woodedpathwoodedpath Registered Users Posts: 9
I'm using a 1hp submersible well pump as one of my 3 dump loads. In the last 3 years I have been through 4 solid state relays. The relay driver is setup to turn on for 5 minutes once voltage is reached and to wait 10 minutes between cycles. There is a low voltage float on the cistern that cuts power to the relay. I'm pumping into a cistern.

The refill rate of the well is more than sufficient for the setup. I ran the pump for 30 minutes last night and this morning with good water flow the entire time. I'm hopping for sun so I can run the pump a few more times today.

I'm starting to feel like I’m abusing the relay but they should hold up to more abuse than what I’m feeding it.

The pump is 220v. 2 wire, and I checked the running at 8.7 to 9.1 amps (checked a few times last night and this morning). I have no idea what the starting amps are.

Can any one suggest quality relay. I would prefer a 12v or 48v control voltage.

Comments

  • BB.BB. Super Moderators, Administrators Posts: 30,625 admin
    Re: 1hp well relay advice

    Sounds like a sweet setup...

    Is there any possibility that the control voltage is getting some surge on it and blowing the input of the solid state relay?

    Do you have a good earth ground for your SW 6048/DC power system? And your AC neutral is grounded? Any lightning in the area? Ratings of Relay?

    For such a large system, try a mechanical relay and see if it lasts? The 6 watts or so for the coil should not be an issue on your size of system (yes, conservation, conservation, conservation. :blush:).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • RCinFLARCinFLA Solar Expert Posts: 1,284 ✭✭✭
    Re: 1hp well relay advice

    Since you say the pump is 220v I assume this to be an AC motor. AC Solid state relays have approximately two diode drops in voltage across them when on.

    At 9 amps and 1.5 volts drop across switch there will be about 13.5 watts of heat dissipation occuring on the switch. This requires a pretty good sized heat sink to prevent the triac device within from getting too hot.

    Approximate heat sink requirement for your situation would be a minimum of a 5"x7" heat sink with 1" fins placed in a location will reasonable air flow.

    Not providing sufficient heat sinking is the most common cause of failure for solid state switches.

    There are DC solid state switches that are a just MOSFET switch and isolation control driver circuitry. Their heat dissipation is dependent on series resistance of MOSFET and current through the switch.
  • mr.radonmr.radon Solar Expert Posts: 158 ✭✭✭✭✭
    Re: 1hp well relay advice

    It could be in rush current. On a cold day that could far exceed the ratings of the solid state relay.
    Most relays are rated for resistive and inductive loads. For a typical relay the inductive load rating is far less then the resistive load rating.
    A good way to solve this is to use the solid state relay to control the solenoid of a high amp AC relay.

    I've had good luck with the G7L. Datasheet.
  • mike95490mike95490 Solar Expert Posts: 8,804 ✭✭✭✭✭
    Re: 1hp well relay advice

    I'm using a 240VAC contactor to switch my pump, it's controlled by the float switch, and a simple intermatic timer. Lasted all last summer with daily cycles. I've decided to go with "standard" old fashioned stuff, because I've got 900' wire runs and lots of chances for spikes and such.
    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 ,

  • woodedpathwoodedpath Registered Users Posts: 9
    Re: 1hp well relay advice

    Yes anything is possible. I don't think I'm getting spikes in the control voltage.

    I have two 8' ground rods about 9' apart at my PV combiner. At the turbine I have two 8' ground rods about 4' apart (I know they should be 8' apart). I have two 8' ground rods about 9' apart at my XW distribution panel. Used 6 gauge solid copper back to the distribution panel.
    The neutral and ground are bonded at the XW panel.
    Some lightning but not much near me.
    The last relay was 40a at 400 to 600 vac, 600v, 5 to 24vdc (using 12 volts supply), with heat sink.

    No I have not tried a mechanical relay. What is 6 watts (lets not go there).


    Yes it's a normal 220v AC well pump.

    The heat sink is an 8” by 8” aluminum with fins.

    The relay (and other smaller relays) is in a 12” by 24” by 8” metal box with no air flow. Never noticed it getting warm to the touch but that would be to late.


    I'll read the datdsheet on the G7L. Looks like it would work.


    So I take it I'm slowly cooking my relay. Would adding one or two 4” filtered cooling fans solve my problem?
  • mike95490mike95490 Solar Expert Posts: 8,804 ✭✭✭✭✭
    Re: 1hp well relay advice

    You can get voltage spikes from just your pump. Long wires, a motor winding, some residual capacitance, and you have a spike at shutoff, when the magnetic field collapses and "kicks" the winding. An 8x8 heatsink shoudl be fine
    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 ,

  • woodedpathwoodedpath Registered Users Posts: 9
    Re: 1hp well relay advice

    It's about 60' to the well and should be about 250' down the well. The well was drilled 4 years ago and has not been pulled.
    Hydro to the XW panel is 50'.
    PV to CC is 20'.

    If it was a voltage spike how would I diagnose it?
  • mike95490mike95490 Solar Expert Posts: 8,804 ✭✭✭✭✭
    Re: 1hp well relay advice
    woodedpath wrote: »
    If it was a voltage spike how would I diagnose it?

    SSR's burn out :-)

    seriously, little spikes can add cumulatively with solid state stuff, and they don't fail instantly. The long wires help limit the starting surge, but can bite you in other areas. I don't know if a MOV protection ckt would help, but I don't see it hurting anything. Step up the voltage spec, use a SSR built for 288V or 480V, should be a lot less resistant to blowing.

    What's the weather at the SSR ? wet, sun baked ??
    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 ,

  • woodedpathwoodedpath Registered Users Posts: 9
    Re: 1hp well relay advice

    I think I might of found part of the issue. I went though everything checking the wire connections and didn't find anything till I pulled the cap off my well. The wires were spilled large wire nuts and electrical tape. I found brittle insulation, melted electrical tape, and one of the wire nuts had a burnt hole in it. I was planning on running the pump for 30 minutes tonight depending on battery voltage but I’ll be putting it off now.

    I'll be picking up a 8 gauge direct bury splice kit and a new relay in town tomorrow.

    The SSR is in my basement. Cool and can get a bit damp from time to time.
  • woodedpathwoodedpath Registered Users Posts: 9
    Re: 1hp well relay advice

    I got the wires in the top of my well fixed. I ran the well for 30 min and checked for heat and didn't feel any.
    I got a new SSR that has a higher ratting installed and picked up a spare.
    I picked up a 12v filtered fan kit and will get it installed this weekend if I get time.

    I did a search for adding MOV but did not find any diagrams on how to use them for what I need. I'm not that good with electronics.
  • LucManLucMan Solar Expert Posts: 223 ✭✭✭
    Re: 1hp well relay advice

    Your starting amp draw on the pump is probably around 50 amps.
    Use a mechanical contactor for reliability in motor starting applications.
  • woodedpathwoodedpath Registered Users Posts: 9
    Re: 1hp well relay advice

    I'm planning on getting a mechanical relay but waiting for a coworker to come and check the start up amps of the pump. I don't know if I will install it right away but would be nice to have one on hand.

    I'm currently thinking that the combination of heat of the SSR and the bad connections at the well is giving me the short life.
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