About MODRATEC Eemeck Electrical Releases
An interlocked frame with Eemeck Electrical Releases applied to levers 4, 7 and 10.
"Why would I need electrical releases?" you ask. Electrical releases are frequently applied to mechanical lever frames in the real world. A typical application is a line clear release. This prevents the signal controlling access to a block section from being cleared unless the signaller at the next location has confirmed that the previous train has left the section. When the signaller sets his block instrument to Line Clear, an electrical signal is sent to the previous signal box that allows an electrical release to be energised to permit the starting signal lever to be pulled. (Only a single pull of the lever is permitted without the whole process being run again.)
MODRATEC's Eemeck releases can be easily added to any LE-series interlocking frame. They may also be retrofitted to interlocking frames of the original series provided before February 2013, although this will involve some modification of the frame and probably a replacement Tappet for each associated release. Please contact MODRATEC to find out what is involved for your specific situation.
The notes above refer to adding electrical releases to a frame that is basically mechanically interlocked. It is possible, however, to build a frame that is purely electro-mechanically locked. This involves using an Eemeck release on each Tappet of the frame and generating electrical logic circuits that permit lever release in response to the state of other levers and external conditions.
Eemeck releases actually latch Tappets in the position from which an electrical release is required. For example, a line clear release latches the lever in its normal (back in the frame) position. It cannot be pulled without being electrically released. Different Tappet configurations allow levers to be latched normal, reverse, or both ways. It is even possible to latch a lever in the central position. This will interest followers of the common Southern Railway practice of using push/pull levers.
Eemeck release assemblies incorporate a frame, actuators, and release push-buttons. The frame is applicable to a pair of Tappets. This relates to the fact that the odd- and even-numbered Tappets are above and below each other in sequence. The actuators have spring-loaded pistons that act vertically on the front of the relevant Tappets. Each actuator has a release push-button that illuminates when release conditions apply. Pressing the button causes the piston to withdraw releasing the Tappet. Release operation is totally silent. (There is naturally a click when a Tappet is latched.) Depending on the type of release required and the specific tappets involved, a frame may carry from 1 to 4 actuators, and there will be the same number of push-buttons. For those who may wish to use a prototypical release plunger (economiser), Eemeck releases can optionally be supplied with flying leads for this purpose.
Eemeck releases require a specific power source. This is derived from a 5V d.c. supply of at lease 0.5A capacity in conjunction with an Eemeck that incorporates power conditioning. A plug pack (mains adapter) is suitable for the 5V supply. A power conditioner may be optionally included with most Eemeck release assembly configurations. You only need one power conditioning unit to operate many releases on the same lever frame.
Note that LE-series interlocking frames are supplied with Type-N Tappets unless you specify otherwise. A Type-N Tappet in conjunction with a single actuator, latches a lever normal and hence requires an electrical release to permit it to be pulled. Here are the types of Tappets available:
- Type-N: Lever latches normal; electrical release to pull. 1 actuator and push-button.
- Type-R: Lever latched reverse; electrical release to return to normal. 1 actuator and push-button.
- Type B: Lever latches both normal and reverse; electrical release to pull or return to normal. 1 actuator and push-button.
- Type-C: Lever latches in the central position; electrical release to push or pull. 2 actuators and push-buttons.