Usage:
Introduction
This chapter contains general installation instructions for the Flo-TechTM Speed Control. Power requirements, ambient temperature limits, and location considerations are included to determine the best location for the control.
Speed Control Installation
Unpacking
Be careful when unpacking the electronic control. Check the control for signs of damage such as bent or dented panels, scratches, and loose or broken parts. Notify the shipper and Woodward if damage is found.
Mounting
The control box is designed to operate within a temperature range of -40 to +70 °C. (-40 to +158 °F).
Mount the control in a location with space for adjustment and wiring access. Do not expose the control to sources of radiant heat such as exhaust manifolds or turbochargers. Choose a protected location so the control won't be damaged when moving the engine or when nearby equipment is moving. Mount the control close enough to the fuel valve and battery to meet the wire-length requirements (see wiring instructions in this chapter).
Do not install the control box directly on the engine.
The control will generate some heat, and surfaces must be open to normal air movement. No special ventilation is required.
Ideally, the control should be mounted flush to the metal side of a control cabinet, protected from the weather and high humidity, and close to the engine being controlled. The location should provide protection from high-voltage or high-current devices, or devices which produce electro-magnetic interference. After initial adjustments are completed, all functions may be selected with remote switches on the control panel. Ready access to the control will not be required for normal engine operation.
Magnetic Pickup
Install the magnetic pickup (MPU) to work with the selected gear through a housing or rigid bracket. Make sure the sensed gear is of magnetic material. Set the gap between the gear and the end of the magnetic pickup according to instructions which accompany the pickup.
Magnetic pickups of various sizes are available from Woodward.
The standard models of magnetic pickups require mating connectors, MS 3102R-18-3P. The connectors can be furnished with the MPU ordered from Woodward.
Manual 82510 Magnetic Pickups and Proximity Switches for Electric Governors contains detailed information on the installation of the sensing device.
Wiring Instructions
External wiring connections and shielding requirements for a typical control installation are shown in the plant wiring diagram (Figure 1-3). These wiring connections and shielding requirements are explained in the balance of this chapter.
Electromagnetic interference (EMI) is the undesirable interaction of electronic circuits with each other and sometimes with themselves.
Woodward Governor Company has established procedures to prevent most EMI which will affect prime-mover-control circuits. Following these procedures is a slight extra expense in planning and installing electronic governing systems, but is inexpensive insurance over the life of the plant. Follow all of the shielding instructions to assure maximum efficiency and dependability of the electronic governing system.
Application Note 50532 EMI Control for Electronic Governing Systems has additional information on EMI causes and prevention.
Shielded Wiring
All shielded cable must be twisted conductor pairs. Do not attempt to tin the braided shield. All signal lines should be shielded to prevent picking up stray signals from adjacent equipment. Connect the shields to the control case as shown in the plant wiring diagram (Figure 1-3). Wire exposed beyond the shield should be as short as possible, not exceeding 150 mm (6 inches). The other end of the shields must be left open and insulated from any other conductor. Do not run shielded signal wires in conduit or bundled with high voltage or high current wires.
Magnetic Pickup Connections
Use 1.0 mm2 or 0.5 mm2 (18 or 20 AWG) shielded two-conductor cable from the magnetic pickup to terminals 5 and 6 on the control. Leave the shield open at the magnetic pickup and ground the shield at the control. Polarity is unimportant.
Speed Trim Connections
If a speed-trim pot is to be used, it should be connected to terminals 9 and 10, as shown on the plant-wiring diagram (Figure 1-3). Use 1.0 mm2 or 0.5 mm2 (18 or 20 AWG) shielded cable with the shield open at the potentiometer and switch connections and tied to chassis ground at the control end.
A 1 kOhms pot will provide about ±2.5 percent speed change from maximum to minimum setting. A 2 kOhms pot will offer about ±5 percent change in speed. Install a single-pole, single-throw switch between terminal 9 and the pot to provide minimum fuel or shutdown when open.
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Do not use the "Open for Min Fuel" switch in the speed trim circuit for emergency shutdown of the engine. The emergency shutdown must be completely separate from the speed control circuit, not depending on the fuel valve or control to provide the shutdown. Life threatening overspeed is possible if a separate overspeed system is not used. |
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A speed-trim pot is often required for loading when the a load sensor is used in the droop mode, or for remote adjustment.
Idle/Rated Switch
Use 1.0 mm2 or 0.5 mm2 (18 or 20 AWG) shielded two-conductor cable to install a single-pole, single-throw switch between terminals 12 and 13 on the control. Leave the shield open at the switch and ground the shield with the other shields on the case.
When the switch is open, the engine will operate at the idle speed. When the switch is closed the engine will operate at the rated speed.
The installation should take into account that the engine will go directly to high speed should the engine restart before the switch is opened. If idle-rated speed selection is not desired, install a jumper (Woodward part number 1606-899) across terminals 9 and 10.
Idle/Rated Dynamics Switch
Connect a single-pole, single-throw switch between terminals 7 and 8. Close the switch for rated dynamics, open for idle dynamics. If desired, a single-throw double-pole switch can be installed on terminals 7-8 and 9-10 to automatically select rated dynamics when rated speed is selected. The switch between terminals 7 and 8 may be connected to a switch that will be closed by the auxiliary breaker switch, if it is desired to go automatically to rated dynamics when the generator unit is paralleled with the bus (loaded). This permits using the idle (slower) dynamics while synchronizing and then changing to the rated (quicker) dynamics when load is applied. Use 18 or 20 AWG stranded wire to connect the switch to the terminals. The wire does not have to be shielded.
Auxiliary Input
If a synchronizer, load sensor, or other speed modifying equipment is used, attach it to terminals 11 (+) and 12 (-). Use 1.0 mm2 or 0.5 mm2 (18 or 20 AWG) shielded, twisted-pair wire to make the connection. Tie the shield to the speed-control chassis. Jumper terminal 11 to 12 if special speed-modifying equipment is not used.
Accel/Decel Ramp
If a ramp generator or a capacitor is used to control acceleration and deceleration rates, connect positive (+) to terminal 10 and negative (-) to terminal 2. Using a capacitor between terminals 10 and 2 will provide about one second of ramp time per 50 ?F. The ramp is non-linear. Use a 50 to 200 ?F capacitor, 15 Vdc minimum working voltage. The capacitor must have less than 30 ?A dc leakage current over the temperature range. If a Woodward Ramp Generator (8271-909) is attached to terminals 10 and 2, the ramp can be adjusted up to 25 seconds from idle to rated speed.
Shields
Ground all shields to one of the bolts used to mount the control. Do not have any of the shields tied to ground at the other end. This is necessary to reduce EMI signals from entering the control with ground loops.
When passing shields through connectors and terminal blocks, treat each shield as if it were a signal wire. Each shield must be given its own pin or terminal and be kept insulated from nearby wires and metal conductors. Do not tin (solder) braided shields.
Connect the speed-control chassis to system ground.