Relay - Motor - Switch ?

tomtucson

New member
When wiring an electric motor with a relay, which is better - Interrupt the power or ground? In this case it is a reel motor which says 35 amps on the label.

Also what amp relay do you want in relation to the motor amps?

When do you want to use a solenoid or something and not a relay?

Thanks
 
Interrupting the power side is normal (typical).

If nothing else will be used on that circuit, a 40A relay should do nicely. Wiring matters, always use the correct gauge (or slightly larger).

Solenoids are just heavy duty relays used for very high amps (think starter on your truck, 400 - 700 Amps).
 
Starter Relay

Electric motors draw quite a bit more current on start-up, than "running amps"..
generally.. 3 to 4 times running amps..
35 x 3 = 105 "starting" amps.. if you use a starter relay rated at 100 amps.. it will probably fail within a year..
Use a relay with "locked-rotor-amps rating of 150+ amps.. and get 4 to 5 years or better.
..let's call that "Long-Term-Low Cost"

the type of relay used on Briggs engines.. 100 amp rating
the type used on big winches & cars.. 300 amps..
..and available at any auto parts store..
12v300a relay.jpg
follow my lead.. and see reliabilty.
 
Make sure if you get a solenoid like Jerry pictured, that it is rated for "constant duty". A Ford style starter solenoid will burn out fairly quickly. You need one like goes on a winch.
 
Do any of you guys sell these solenoids or have a model number/supplier that sells them that will work on large hose reels?

Thanks.
 
Do any of you guys sell these solenoids
.. or have a model number/supplier that sells them that will work on large hose reels?
Thanks.

They will work great on big hose reels
I stock'em, with all connectors, and fuses, etc.
..you knew that.
..Wouldn't you normally turn to a HotRod shop for HotRod parts ??
..We are custom everything.

:{)
 
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