Motor Circuit Protectors

Sprecher + Schuh Motor Circuit Protectors

KT7 Control and Protection to 45A UL Approved for a Wide Variety of Applications

Sprecher + Schuh's KT7 series of Motor Circuit Controllers are some of the most versatile and technologically advanced control products available today. These devices can be used in a variety of control schemes that reduce panel space, simplify installation and eliminate the need for more expensive equipment.

Variety of models... Increased ratings...

Sprecher + Schuh's KT7 controller family offers higher interrupting capacities (KAIC ratings), improved Type 2 Coordination and a midsize frame rated to 45A. In addition, the line includes "high break" 25A and 32A devices which offer greater withstand ratings in a smaller frame size.

Designed for multiple applications UL rules allow KT7 Motor Circuit Controllers to be used in a wide variety of applications, including:

Multi-motor applications

Popular and money saving Because of KT7's Construction Type E-UL Rating as a self-protected combination starter, many group motor installations can utilize an even simpler design and less expensive equipment. The result is minimum panel size and maximum flexibility while avoiding cumbersome NEC group motor rules. 60mm Bus Bar systems can be utilized to provide a cost effective and flexible multi-starter panel assembly.

For design assistance or technical clarification on multi-motor or bus bar systems contact Technical Support.

Excellent short circuit protection characteristics Approaching 3/1000 of a second. This results in the extremely rapid buildup of an arc voltage which limits the current of the short circuit to a very low level. Because of this superb current limiting capability, KTA Motor Circuit Controllers have a short circuit capacity of up to 65kA at 480V and up to 47kA at 600V.

Superb thermal overload protection

Every KT7 device is individually calibrated at the factory for the smallest and largest current it can handle. When coupled with automatic ambient temperature compensation over a range of -25°C to +60°C, very accurate thermal overload protection is obtained. In addition, the KT7 is a Class 10 device. It trips within 10 seconds under locked rotor conditions (6 x FLA). This better protects today's T-Frame motors.

Construction Type E Listing

Improved current limiting and breaking capacity has allowed KT7s to be UL / CSA listed as self-protected (Construction Type E) manual combination motor controllers. This eliminates the need for an upstream fuse or circuit breaker when using the KT7 as a manual motor starter. In addition, KT7s also meet UL requirements for "at-motor disconnects," which means they can be used in an enclosure with a lockable handle as a manual motor starter for individual circuits, and are also an approved means of motor disconnect.

Reference: Methods of applying KT7 motor circuit controllers

Type E + combo starter + economy = "Ecombo" starter.

When the KT7 self-protected manual combination starter is combined with Sprecher + Schuh's CA7 contactor to provide remote operation, we now have an alternative to the classic combination starter. We call these "Ecombo" starters, which save significant dollars and panel space over conventional combo starters. Ecombo starters are available for applications up to 30HP (@460/600V).

Special units for special applications KTC7 controllers are available with a fixed magnetic trip set at 16...20x the maximum value of the current adjustment range (as opposed to 13x for the KTA and KTB7). This prevents nuisance tripping in applications utilizing high efficiency motors for example.

The KTB7 model is available without the thermal trip feature if a separate motor overload is required. Combine KTB7 with a CA7 Contactor and CEP7 Overload Relay to create the CLT7 3-component Ecombo starter.

Other protection features All KT7 Motor Circuit Controllers provide accelerated tripping under single phase conditions. This is accomplished with a special "differential tripping" mechanism built into each device.

Carlo Gavazzi Manual Motor Starters


  • Protection of group installation
  • Protection of circuits
  • Motor protection
  • Starter protection
  • Wide range of ambient termperature compensation
  • Phase failure protection


  • 45mm width up to 32A, 55mm width up to 63A, and 70mm width rated to 100A
  • Three position operator: On/Off/Trip (Only 100AF is applied)
  • Complete range of common accessories
  • Handle lock in the OFF position
  • Class 10, 20 overload trip characteristics
  • Trip test
  • Finger safe terminal
  • DIN rail and screw mounting


  • The components fulfill the international standard IEC 60947
  • The devices can be used as Manual Motor Starters in Group Installations according to UL508 & CSA C22.2 as Manual Motor Controllers (Type "E" starters)

Building a multi-motor control panel?

Why not take a GMS32A, couple it to a Carlo Gavazzi CC contactor via a GDA32HA coupler, then install this combination starter onto a GMU45 backplate. Then install this starter on a DIN rail.

Next place as many combination starters as may be required for the complete controller all onto the same DIN rail. Install an MSVGW45 Link set across the top of up to 5 combination starters, install an MSVGWE1-14 Main lug and the complete group of starters can be fed from a single power source.

Note: Multiple MSVGW45 Link sets can be combined to connect more than 5 combination starters to a single power source (within the 63A rating of the MSVGWE1-14 Main lug).

MCPs stacked by MSVGW45-14-3 Link set Thermal Release Trip Current: The adjustable inverse bimetal trip reliability protects motors against overloads and additionally provides motor protection even in the case of single-phasesing.

Magnetic Release Trip Current: The instantaneous magnetic trip has a fixed operating current setting that corresponds to 13 times the maximum value of settin range.

For a complete PDF on Carlo Gavazzi Motor Circuit Protectors (MCP), press HERE. Note: The PDF is quite large and may take a minute or more to load.

Electram Rotary Equipment Ltd stocks most Carlo Gavazzi MCP Motor Circuit Protectors and associated controls in our Edmonton, Alberta, Canada facility.

MSVGWE1-14 Main Lug & GDA22HA coupler

GMU45 DIN mount base

Motor Circuit Protectors

Motor Circuit Protectors

Multi-motor Control Panel
with 4 Motor Circuit Protectors