Abstract A motor controlling system, including a conventional multipole electromagnetic contactor and associated overload relay means, is provided with motor short-circuit protector means in the form of fast-acting fused protector means connected in series with the heaters of the overload relay means and the motor windings. Under overload conditions below locked rotor current, referred to as running overloads, the overload relay means opens the actuating circuit for the contactor holding coil, and under severe fault conditions the fused protector means becomes active to limit letthrough energy to a level that will not damage either the motor, contactor, overload relay means, or wiring to the motor. The overload relay means is chosen from a family of overload relays in which each relay is adapted to protect a motor drawing a different full load current and the fused protector means is chosen from a family of fused protectors in which each protector is adapted to coordinate with a plurality of different relays from said family of overload relays. Actuation or melting of a fused protector unit causes an ejector pin thereof to operate a common trip bar which, in turn, opens a switch in the coil circuit. This trip bar is part of an antisingle phasing unit that is selectively positionable with respect to the clips which mount the fused protector units, thereby cooperating with fused protector units of different sizes. These clips are provided with integral formations which serve a blocking or non-interchangeability function, thereby preventing oversized fused protector units from being mounted to the clips.
Mounting means for removably connecting a motor short circuit protector (MSCP) in a motor starter circuit, with this MSCP being from a family consisting of at least three MSCPs each having a different let-through energy rating, each having the same length cylindrical body and the same diameter axially extending cylindrical terminals at each end, with body diameter and terminal length in the family being graduated so that they are greatest for the MSCP of highest rating and least for the MSCP of lowest rating; said mounting means including first and second clips engaging the cylindrical terminals of an MSCP, said clips being spaced apart by the same distance regardless of the highest rated MSCP said spring clips are constructed to receive; at least one of said clips at the end thereof remote from the other of said clips having a blocking means operatively positioned to permit normal mounting of those MSCPs in said family having ratings below a predetermined let-through energy rating and block mounting of those MSCPs in said family having ratings above said predetermined let-through rating.
Claim 2
Dependent Claim
178 words
Mounting means for removably connecting a motor short circuit protector (MSCP) in a motor starter circuit, with this MSCP being from a family consisting of at least three MSCPs each having a different let-through energy rating, each having the same length cylindrical body and the same diameter axially extending cylindrical terminals at each end, with body diameter and terminal length in the family being graduated so that they are greatest for the MSCP of highest rating and least for the MSCP of lowest rating; said mounting means including first and second clips engaging the cylindrical terminals of an MSCP, said clips being spaced apart by the same distance regardless of the highest rated MSCP said spring clips are constructed to receive; at least one of said clips at the end thereof remote from the other of said clips having a blocking means operatively positioned to permit normal mounting of those MSCPs in said family having ratings below a predetermined let-through energy rating and block mounting of those MSCPs in said family having ratings above said predetermined let-through rating.
Claim 3
Dependent Claim
40 words
Mounting means as set forth in claim 1 in which each of said clips includes a pair of spaced jaws; said blocking means including inward projections on said jaws of at least one of said clips and formed integrally therewith.
Claim 4
Dependent Claim
50 words
Mounting means as set forth in claim 2 in which each of the clips is generally U-shaped with a web section connecting a pair of spaced arms constituting said jaws, said web being at one end of said arms and said projections being at the other end of said arms.
Claim 5
Dependent Claim
29 words
Mounting means as set forth in claim 3 in which the projections of one of said clips are at the end thereof remote from the other of said clips.
Claim 6
Dependent Claim
115 words
Mounting means as set forth in claim 2 in which both of said clips have inward projections on said jaws formed integrally therewith and operatively positioned to reject predetermined devices exceeding said predetermined specifications from being operatively mounted to said clips; for each of said clips the inward projections thereof being at the end thereof remote from the other of said clips; said clips being positioned with the spacing between the projections of said first clip and the projections of said second clip being greater than the overall lengths of those electrical devices of no greater than said predetermined specifications and being less than the overall lengths of those electrical devices exceeding said predetermined specifications.
Claim 7
Dependent Claim
50 words
Mounting means as set forth in claim 5 in which each of the clips is generally U-shaped with a web section connecting a pair of spaced arms constituting said jaws, said web being at one end of said arms and said projections being at the other end of said arms.