Rapido RailCrew Switch Machine Power Supplies

  This page has information on power supplies for Rapido's RailCrew Switch Machines. The page also provides options for controlling RailCrew switch machines.

  This page does not cover the installation of the RailCrew switch machines. An installation video can also found on Youtube at RailCrew Switch Machine Installation Video and on the Rapido web site.

RailCrew Switch Machine And Basic Power Supplies

  The voltage and current values shown on the next diagram are based on measurements using one of the RailCrew switch machines.

  Most modern power supplies have internal overload protection but why abuse them any more than necessary. The wallwart in the junk drawer might work with the RailCrew switch machine but will be subject to large current draws that may eventually damage it.

  The switch machine has a built-in, self-resetting circuit breaker but in the time it takes to open the circuit some power supplies could be damaged.

  If two machines need to be thrown together, such as at a crossover, their coils could be wired in series.

  If a machine throws in the wrong direction after it is installed, the supplied terminal block can be removed and rotated 180 degrees. The auxiliary contact connections will not need to be changed because they are symmetrical.

Motor Overload Protection Device Test

  For a test: A current of 2 amps from a 9 volt supply was applied to the switch machine's motor. ( The current dropped as the element in the overload protector and the windings became warmer. )

  The protector opened the circuit after 1 minutes and 20 seconds and reset after approximately 8 minutes. While waiting for the protector to reset, the case of the machine became noticeably warmer to the touch.

  For this test the switch machine was sitting on a table in open air. When mounted on the layout it may take longer to reset the protector.

  Larger applied currents would cause the protector to open more quickly but would also generate more heat during the tripping time.

  Throwing the machine in typical switching operations and only briefly holding the toggle switch closed should not cause the protector to trip.

Controlling RailCrew Switch Machines Using Toggle Switches And Capacitors

  The following link has circuits for single coil switch machines. The circuits allow LEDs to indicate the alignment of the turnout and control from more than one location.

Controlling Single Coil And Twin Coil Switch Machines With SPST Toggle Switches.

Controlling RailCrew Switch Machines Using Push Button Switches And Capacitors

  Push button switches can be used to control RailCrew switch machines by using a dual capacitor discharge power supply.

Controlling Single Coil Switch Machines With Push Buttons

Capacitor Values

  The value of the capacitors in these circuits are only a suggestion. Smaller values may work equally well for a particular switch motor or larger values may be needed for less sensitive machines.

Other Capacitor Discharge Power Supply Information

Other Circuits

Control Using ON-ON Type DPDT Toggle Switches

  The following circuit uses a ON-ON type DPDT toggle switch to control a Rapido switch machine from a capacitor discharge power supply system.

  The handle of the toggle switch can also be used to indicate the position of the turnout.

  Circuit #2 on the schematic is based on this CD power supply circuit.

Control Using ON-ON Type DPDT Toggle Switches

  The following circuit also uses a ON-ON type DPDT toggle switch to control a Rapido switch machine but interrupts the coil circuit each time the motor throws.

  This method is not ideal because it ties up one of the sets of internal contacts and subjects them to high currents as well.

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Please Read Before Using These Circuit Ideas

  The explanations for the circuits on these pages cannot hope to cover every situation on every layout. For this reason be prepared to do some experimenting to get the results you want. This is especially true of circuits such as the "Across Track Infrared Detection" circuits and any other circuit that relies on other than direct electronic inputs, such as switches.

  If you use any of these circuit ideas, ask your parts supplier for a copy of the manufacturers data sheets for any components that you have not used before. These sheets contain a wealth of data and circuit design information that no electronic or print article could approach and will save time and perhaps damage to the components themselves. These data sheets can often be found on the web site of the device manufacturers.

  Although the circuits are functional the pages are not meant to be full descriptions of each circuit but rather as guides for adapting them for use by others. If you have any questions or comments please send them to the email address on the Circuit Index page.

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22 March, 2018