On 12/28/2011 1:25 PM, Ray Benny wrote:
> Tnx to all who replied. I'm going to purchase a larger switch from
> Mouser.com that should handle the current.
>
> Ray,
> N6VR
>
> On Wed, Dec 28, 2011 at 11:17 AM, AI4WM Bill<ai4wm@yahoo.com> wrote:
>
>> Depends on the internal construction of the contacts. Switching and
>> inductive load may flash them when switched off. Then locked rotor current
>> may be upwards of 45 amps for a few milliseconds until the armature starts
>> to rotate. Locked rotor all depends on the starting load and the
>> efficiency of the motor.
Generally when you get to that size they recommend using a contactor. I
have a 5 HP motor used in a rotary phase converter. It says specifically
not to use switches or circuit breakers, but use a contactor with
overloads to provide power to the motor.
Fortunately I was given, (traded) for a NEMA size 2 contactor with 30A
overloads. The contactors alone run between $500 and $600 retail.
Parts? Head for e-bay! Lots of contactors and parts for a fraction of
retail.
73
Roger (K8RI)
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