0384500 JOHNSON CARBURETOR ASSY., Complete

Read this entire manual and all other publications pertaining to the work to be performed before installing, operating, or servicing this equipment. Practice all plant and safety instructions and precautions. Failure to follow instructions can cause personal injury and/or property damage.The engine, turbine, or other type of prime mover should be equipped with an overspeed (overtemperature, or overpressure, where applicable) shutdown device(s), that operates totally independently of the prime mover control device(s) to protect against runaway or damage to the engine, turbine, or other type of prime mover with possible personal injury or loss of life should the mechanical-hydraulic governor(s) or electric control(s), the actuator(s), fuel control(s), the driving mechanism(s), the linkage(s), or the controlled device(s) fail.
To prevent damage to a control system that uses an alternator or battery-charging device, make sure the charging device is turned off before disconnecting the battery from the system.
Electronic controls contain static-sensitive parts. Observe the following precautions to prevent damage to these parts. * Discharge body static before handling the control (with power to the control turned off, contact a grounded surface and maintain contact while handling the control).* Avoid all plastic, vinyl, and styrofoam (except antistatic versions) around printed circuit boards.* Do not touch the components or conductors on a printed circuit board with your hands or with conductive devices.
Application
The 721 Digital Speed Control controls the speed and load of reciprocating engines in generator set service, including those with flexible couplings (see Figure 1-1). The control includes inputs for two magnetic pickups (MPUs) or proximity switches for monitoring flexible coupling torsionals, an input for a 4 to 20 mA remote speed or load setting, an input for output fuel limiting, an internal speed reference for local control of speed, and an input for a KW load sensor and load sharing connections for load sharing applications.* a 721 Digital Speed Control;* an external power source;* one or two speed-sensing devices (as required);* a proportional actuator to position the fuel rack;* a terminal for adjusting control parameters;* an optional KW load sensing device;* an optional boost pressure or rack position sensing device for fuel limiting.
Figure 1-1. Flexible Coupled Generator SetThe 721 control (Figure 1-2) consists of a single printed circuit board in a sheet-metal chassis. Connections are via three terminal strips and a 9-pin subminiature D connector.Control Options
The 721 control requires the following power supply input voltages, with 18 watts as the nominal power consumption at rated voltage: * low voltage - 18-40 Vdc (24 or 32 Vdc nominal);* high voltage - 88-132 Vac 45-65 Hz (120 Vac nominal) or 90-150 Vdc (125 Vdc nominal).Discrete input voltages provide on/off command signals to the electronic control, such as Raise Speed/Load, Lower Speed/Load, etc. Each discrete input requires 10 milliamps at its 24 Vdc nominal voltage rating (for 24 volt switching logic).Other control options are: * proximity switch input for speed signal frequencies below 100 Hz;* tandem actuator outputs.Magnetic pickup versions are limited to operating speeds providing 60 Hz magnetic pickup frequency minimum.721 Digital Speed Control Accessories
Hand Held Programmer (Figure 1-3), part number 9905-292, is used for adjusting the 721 control. It plugs into the serial port of the control.SPM-A Synchronizer, for synchronizing the generator phase to that of the power bus. The synchronizer generates a close generator breaker signal to parallel the generator with the power bus.Real Power Sensor, for load sharing or droop-parallel generator applications.
Figure 1-2. 721 Digital Speed Control
Figure 1-3. Hand Held Programmer
Figure 1-4. Simplified Block Diagram
Figure 1-5. Detailed Block DiagramPlant Wiring DiagramNOTES:1. Shielded wires are twisted pairs, with shield grounded at one end only. When mounting control to bulkhead, use the grounding stud and hardware supplied with the chassis to ensure proper grounding.2. Shields must not be grounded at any external point unless otherwise noted.3. All shields must be carried continuously through all terminal blocks and must not be tied to other shields except at the common ground point. The shields are tied together at the ground stud.4. Remove jumper for voltage input.5. Close for isochronous, open for droop.6. Analog input signals from other systems must be isolated from ground either by design or employment of isolation amplifiers.7. Analog output signal to other systems must be isolated from ground either by design or employment of isolation amplifiers.8. Discrete inputs are isolated from other circuits and intended to be powered by the same source as control supply voltage. Input current is nominally 10 milliamperes per input into 2100 ohms.9. Unless otherwise specified: A. relays shown de-energizedB. relays energize for functionC. relay contact ratings for minimum 100 000 operations: resistive - 2.0 amperes at 28 Vdc 0.1 amperes at 115 Vac 50 to 400 Hzinductive - 0.75 amperes at 28 Vdc 0.2 henry 0.1 amperes at 28 Vdc lamp10. Confirm each connection before operating unit.11. Factory set for MPU input.12. Factory set for 20-160 mA output.13. Factory set for 4-20 mA output.14. Use RIS PCE-20 series transducer or Woodward Governor Real Power Sensor 8272-387 or 8272-394.15. These analog outputs may connect to metering/controlling devices. The shield should be continuous between all connected devices with a single shield termination point to ground.16. Internal power supply provides dc isolation between the power source and all other inputs and outputs.17. Terminals marked "NO CONNECTION" must remain open.18. When using remote load or speed reference input, analog input or remote select must be removed when switching aux input at terminal 32.19. Speed reference is selected when terminal 32 is open. Load reference is selected when terminal 32 is closed.20. See option chart.21. Put jumper in for high-voltage power supply units only (9905-381); otherwise, leave jumper out.
Figure 1-6. Plant Wiring Diagram
Figure 1-7. Typical 721 Connections