On Mon, 9 Mar 2009 08:36:45 -0700 (PDT), jtpryan
wrote:

So could there be something amiss with the DC as it blows a 15 amp
breaker?

Immediately, or after it runs for a few seconds? What does the motor
dataplate list for amperage at 120v?

A DC is typically harder starting than a TC because of the rotary
inertia of the impeller. That will extend the DC's startup current
inrush for a longer time as compared to the TC. That's why
manufacturers of most DC's recommend a limit on number of starts per
hour.

Residential type circuit breakers are not usually instantaneous trip
and will tolerate a considerable overload for a short period - the
higher the overload, the shorter the period. So the breaker you have
should tolerate the startup "spike". But, If the DC is hard enough to
start and the running current is close enough to the breaker rating,
the starting inrush could last long enough to trip the breaker.

1.5 HP is getting pretty close to the limit for a 120v/15a circuit
even for a high efficiency motor. And a 120v/20a circuit is definitely
too small for a 1.5HP DC and a 13amp TS.

Tom Veatch
Wichita, KS
USA