Does a 30 amp spdt switch exist?

Discussion in 'General Electronics Chat' started by OGRE, Jun 16, 2013.

  1. OGRE

    Thread Starter Member

    May 31, 2013
    41
    0
  2. tubeguy

    Well-Known Member

    Nov 3, 2012
    1,157
    197
    Your switch has a HP rating of 3/4. Check the blower HP rating.
    If the blower motor is around 1/2 HP or less, should be OK.
    It's usually a good idea to operate components at less than max. rating.
     
  3. OGRE

    Thread Starter Member

    May 31, 2013
    41
    0

    So if the hp is correct its ok to run 30 amps into the switch? Just want to be sure I don't run the wrong amount of amp's into the switch. Thanks for the fast response.
     
  4. tubeguy

    Well-Known Member

    Nov 3, 2012
    1,157
    197
    30 amps is the maximum the circuit can supply. The motor will draw only the current it needs through the switch. The switch rating is based on the motor current or horsepower rating, not the circuit rating. As a side note, AC circuits should not be loaded at more than 80% of the circuit rating, or whatever the local codes require.
     
    Last edited: Jun 16, 2013
  5. #12

    Expert

    Nov 30, 2010
    16,298
    6,810
    Not much left to say here. The switch is running the motor, not the circuit breaker. If the switch is rated to run a motor that size, go for it.
     
  6. OGRE

    Thread Starter Member

    May 31, 2013
    41
    0
    Thanks so much. Heres the info off the motor. Nothing wrong with triple checking.

    208/230v
    1/2hp
    A. 2.90
    HZ. 60
    Ph. 1
     
  7. OGRE

    Thread Starter Member

    May 31, 2013
    41
    0
    After burning up my last motor I don't want to take chances.:confused:

    Finally got this thing mounted like I wanted just need to add filters, junction boxes, and switch to tidy thing up.
    [​IMG]
     
  8. tubeguy

    Well-Known Member

    Nov 3, 2012
    1,157
    197
    Triple checking is sometimes a good thing....

    Heavy Duty Toggle Switch, Single Pole Double Throw, On/Off/On, Screw Terminal, Recommended Mounting Hole Fits 1/2" Diameter, 20A/125V, 3/4 HP, Carded.

    Switch: HP OK, Voltage Not OK . Need a 208/230 volt rated switch. :rolleyes:


     
  9. #12

    Expert

    Nov 30, 2010
    16,298
    6,810
    Here is a limitation: Those fans are designed to fight against air flow restriction in the ductwork. The more air they can get at the intake, the more power they will use. Check the running amps to be sure you aren't going over the current limit (2.90 amps). If the current is too high, you will have to reduce the intake air by using some kind of partial (mechanical) obstruction.

    ps, tubeguy caught the voltage error:(
     
  10. OGRE

    Thread Starter Member

    May 31, 2013
    41
    0
    Glad I triple checked. The switch I have in hand says:

    10A 277 V AC/ 20A 125 V AC
    3/4 HP 125-250 V AC

    Since the motor only needs 2.9 amps, and 10A/ 277 V covers that correct?
    That means I could potentially run this switch at 10 max on 277 V max right?
    I don't think the motor is pulling either of those.

    As for air restriction. I will be installing a series of filters on the intake side of the blower.
     
  11. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
  12. OGRE

    Thread Starter Member

    May 31, 2013
    41
    0

    ???


    After testing the motor is pulling 2.5 amps.
     
  13. Duane P Wetick

    Active Member

    Apr 23, 2009
    408
    19
    You should be using a manual on-off motor starter for 3/4 HP motors and not just a simple switch...the reason is the motor starter will protect the motor from burning up or otherwise overheating...the are in-expensive enough...look in E bay's industrial section.

    Cheers, DPW [ Everything has limitations...and I hate limitations.]
     
Loading...