Results 1 to 15 of 15
  1. #1
    Member kybob's Avatar
    Join Date
    Apr 2005
    Location
    Greenup, KY
    Posts
    945

    Question Electrical Question - Garage door opener motor.

    Planning on purchasing a Chamberlain 1 1/4 hp garage door opener. Wanting to know how many amps motor is pulling when door is opening/closing. Really wanting to know if I can put more than 1 opener on a 20 amp breaker. Roughing in boxes on 4 doors. Planning right now on getting 2 openers.

  2. Member
    Join Date
    Nov 2012
    Location
    Gretna, NE
    Posts
    5,919
    #2
    What model nr is the opener wasn't aware that chamberlain made anything larger then 3/4 hp. I think all the motors have changed to P3 motors which use a European measurement. Can't recall what it is called. I do know that a 1 1/4 hp opener would be a waste of money as the movement of the door is all in the springs and the proper balancing of the door.
    John the Garage Doorman

  3. Member Obsessed's Avatar
    Join Date
    Jan 2014
    Location
    West Plains, Mo
    Posts
    3,205
    #3
    Here is what I find. So a 1/2 hp would be about 7 amps.

    I have seen where people have three different 1/2 hp openers and they say they can run all three at once without tripping the breaker.

    As a "rules of thumb" amps horsepower rating can be estimated to

    • 115 Volts motor - single-phase : 14 amps/hp
    • 230 Volts motor - single-phase : 7 amps/hp
    • 230 Volts motor - 3-phase : 2.5 amps/hp
    • 460 Volts motor - 3-phase : 1.25 amps/hp
    2017 Ranger RT188, Dual Console, Crystal Red Metallic, Mercury 115 Pro XS Four Stroke, Command Thrust with Tempest 24P, 52 MPH GPS @ 5200 RPM
    Motor Guide 80 lb Xi5 Pin Point/GPS , Lowrance HDS 7 w/Totalscan @ Console, Lowrance Elite 7 TI @ Bow; Romans 6:23

  4. Member
    Join Date
    Dec 2010
    Location
    Franklin,OH
    Posts
    642
    #4
    You can run one circuit for two no problem. I wouldn't go three even though the odds would be slim they would all start at once. The electrical code requires gfci protection at least in Ohio so if that's the case more than one circuit would be a plus in case that gfci was to trip.

  5. Member kybob's Avatar
    Join Date
    Apr 2005
    Location
    Greenup, KY
    Posts
    945
    #5
    Thanks all so far. Reason for going to the 1 1/4 hp is I have 16 X 10 & a 14 X 10 insulated door that they are going on. If 1 door will draw 14 amps or so, then I should put each door on there own breaker

  6. Member
    Join Date
    Dec 2010
    Location
    Franklin,OH
    Posts
    642
    #6
    Your right if its drawing 14 amps then run a dedicated 20 amp circuit for each

  7. Member 1BADAIR's Avatar
    Join Date
    Dec 2014
    Location
    OXFORD MI
    Posts
    3,895
    #7
    I would also check into a jackshaft opener
    2011 Ranger z521/2023 250ProXS

  8. Major Flagelator Gamblinman's Avatar
    Join Date
    Jun 2004
    Location
    Yantis, TX
    Posts
    4,121
    #8
    I run 2 openers on a 20A circuit, sometimes at the same time. Never a problem.
    "Better to remain silent and be thought a fool than to speak out and remove all doubt."

  9. Member
    Join Date
    Jun 2004
    Location
    Kennebunkport, Maine
    Posts
    1,357
    #9
    Quote Originally Posted by kybob View Post
    Thanks all so far. Reason for going to the 1 1/4 hp is I have 16 X 10 & a 14 X 10 insulated door that they are going on. If 1 door will draw 14 amps or so, then I should put each door on there own breaker
    If the doors are adjusted good with proper tension on the spring. It takes almost no effort to open the door. I have 3 10x10 on one 20 amp circuit. I am though only using 3/4 HP openers as well.

  10. Member
    Join Date
    Nov 2012
    Location
    Gretna, NE
    Posts
    5,919
    #10
    Quote Originally Posted by kybob View Post
    Thanks all so far. Reason for going to the 1 1/4 hp is I have 16 X 10 & a 14 X 10 insulated door that they are going on. If 1 door will draw 14 amps or so, then I should put each door on there own breaker
    For 10 ft high doors don't use chamberlain openers they only come as multi piece rails, you will have a lot of flex in the rails. Call a lift master dealer and purchase a commercial door opener model MT-50L4-10. They come with safety eyes and a built in radio receiver. They are only 1/2 hp openers but I've used them on doors as large as 18X14 I think they are duty rated for doors up 250 sq feet.
    John the Garage Doorman

  11. Member kybob's Avatar
    Join Date
    Apr 2005
    Location
    Greenup, KY
    Posts
    945
    #11
    Quote Originally Posted by Doorman1 View Post
    For 10 ft high doors don't use chamberlain openers they only come as multi piece rails, you will have a lot of flex in the rails. Call a lift master dealer and purchase a commercial door opener model MT-50L4-10. They come with safety eyes and a built in radio receiver. They are only 1/2 hp openers but I've used them on doors as large as 18X14 I think they are duty rated for doors up 250 sq feet.
    Thanks Doorman 1, I had just googled a few minutes ago and lift master was the first manufacturer to come up. Will try to find a dealer near me. Thanks Again and MERRY CHRISTMAS.

  12. Member
    Join Date
    Apr 2012
    Location
    Insomnia, near Seaford Delaware
    Posts
    35,510
    #12
    Quote Originally Posted by GaryL View Post
    If the doors are adjusted good with proper tension on the spring. It takes almost no effort to open the door. I have 3 10x10 on one 20 amp circuit. I am though only using 3/4 HP openers as well.
    Very true. Another thing, the only time that motor will pull anywhere near the rated amperage is when it starts to move. That is, unless you forget to remove the door latch, and then if you have a 1&1/2 HP it will break something.

  13. Electrical/Wiring/Trolling Motors Moderator CatFan's Avatar
    Join Date
    Jun 2004
    Location
    SW Indiana
    Posts
    26,089
    #13
    The current a motor draws depends on its load. A 1HP motor and a 1/4HP motor will draw virtually the same current doing the same job. So if you have a good installation of the doors, it would be easy to get three openers to run on one breaker, and motor size will make little difference. If the doors bind or the springs are out of adjustment, you might have problems.
    If you have integrity, nothing else matters. If you don't have integrity,
    nothing else matters.​

  14. Ohio Fishing Reports Moderator omcforever's Avatar
    Join Date
    Nov 2007
    Location
    Miamisburg Ohio/Formerly Aiken SC
    Posts
    20,052
    #14
    Put an amp clamp on it and watch it at initial start and thru its operation. Gives you actual initial amp draw and constant amp draw. Compare it to motor rating. Tells you everything you need to know.

    Age and treachery will always overcome youth and skill !!

  15. Member
    Join Date
    Sep 2016
    Location
    Louisville Ky
    Posts
    15,367
    #15
    Also depends on if the MFG is giving starting HP / current or running HP / current. Such as the big box compressors love to state they are 5hp.. In reality when you check out the specs they arent anywhere near 5hp. Typically they rate the starting current which is where they get the 5hp rating from. I saw one that was so bad the only thing I can think is they were rating it based on stall or something.