Series KT7 Motor Circuit Controllers
Versatile, convenient and space saving.... for a 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.
In one small package, KT7s combine the functions of:
- Current limiting short circuit protection
- Class 10 thermal overload protection
- Switching and
- Signaling
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.
Increased ratings
Sprecher + Schuh's KT7 controller family offers higher interrupting capacities (KAIC ratings) and improved Type 2 Coordination and Type E (life after short-circuit). The KTA7-25H/32H offers the option of higher short-circuit current ratings (SCCR) than the standard interrupting capacity of the KTA7-25S/32S Motor Controllers. KTA7 is also available in frames up to 45A. KTC7 can be used with High Efficiency motors. KTB7 Magentic Only controllers can be combined with CA7 contactors and CEP7 overloads to provide additional features.
Designed for multiple applications
UL rules allow KT7 Motor Circuit Controllers to be used in a wide variety of applications including:
- Manual Starter Applications
- Traditional Group Motor Applications with compliance to the new Tap Conductor Ratings
- Motor Disconnect Applications
- Self-Protected Manual Combination Starter Applications (Type E)
- Individual Combination Starter Applications (Type E/F)
- Multi-motor Starter Combination Applications (Type E/F)
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.
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 45 Amperes.
Multi-motor applications... Popular and money saving
Because of the 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 installations rules.
Excellent short circuit protection characteristics
In the event of a short-circuit, the contacts are opened by magnetic, non-adjusting tripping elements in times approaching 2/1000 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 480Y/277V and up to 47kA at 600Y/347V .
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 degree Celsius to + 60 degree Celsius, 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.
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 KTA7). This prevents nuisance tripping in applications utilizing high efficiency motors for example. The KTB7 Magnetic Only model is available without the thermal trip feature for special applications where a separate motor overload is required.
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.
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