Allen-Bradley 440T-MRKSE110A Bulletin 440T safety-rated box-mounted single key rotary switch with 20A current rating, 2 normally open / 2 normally closed (2NO/2NC) contact configuration, and IP65 enclosure rating for dust and water jet protection. Designed for safety interlock and access control applications requiring a key-operated selector function.

Product Details

Allen Bradley Guardmaster - RKSE series security keys mounted on electrical control unit

Provide enhanced security and stability for your machine guard safety process and protect personnel with the Prosafe RKSE Series Rotary Key Switch box by Allen Bradley Guardmaster.
This trapped key unit isolates power to machinery when the coded key is removed, ensuring that personnel cannot access dangerous areas where machinery may be in motion. This unit is perfectly designed for safety applications which require a pre-defined sequence of operations to access machinery. This type of reliable mechanical interlocking device is usually used in environments where electrical interlock systems may be unsuitable or expensive to install and maintain, such as areas with explosive atmospheres.
To remove the key it must be rotated 90° anti-clockwise. This alters the state of the positively guided switch contacts. The contacts can be reverted to their original state by re-inserting the key and rotating it 90° clockwise, which will trap it again.

Features and Benefits:

New range of rotary switch interlocking systems: the new keys are compatible with the old barrels, although they have an additional notch (old keys will not fit the new barrels)
Secure trapped key interlocking system allows access to machinery only after power has been switched off
Key locked, switch ON; key released, switch OFF
Surface-mounted housing
IP65 rated – total protection against dust ingress and durable against low pressure water jets
Robust stainless-steel housing for exceptional durability
Key must be ordered separately.
The Prosafe range of products have been extensively tested for quality and durability, working seamlessly for 100, 000 operations. They are also highly tamper-resistant, accepting only the original or equivalent new key for operation. Allen Bradley Guardmaster have one of the broadest portfolios in the industry for machine safety products, which ensures that you can create your ideal safety system and keep your operations running smoothly.

Standards

EN 292 and EN 1088, IEC 947-5-1, ULandCSA
The 440T-MRKSE110A rotary switch unit is single key and has 2 NO & 2 NC contacts, 20 Amp current, and M20 conduit entry.

How does a trapped key interlock work?

A trapped key interlock is a simple sequential mechanical safety system for machine guards whereby a removable key is trapped in a control device while the power supply is running. Only when the power supply is turned off can the key can be rotated in the lock and withdrawn. While it is removed the power supply is isolated, ensuring that the machine cannot be restarted while the guard door is open. The key can then be used to release the machine guard door, allowing access to the machinery. After the guard door is closed it can be removed and inserted back into the original control device, thus allowing the power supply to be activated again. Trapped key interlocks can withstand harsher environments than electrical interlocks and are often used in industrial settings where serious risk of injury can occur to machine operators.

Trapped Key Switch