Application & Installation Guide Starting Systems LEBW4980-10
Contents Starting Systems ...............................................................................1 Starter Types ................................................................................ 2 Electric Starting..................................................................................3 Batteries ................................................................................... 4 Lead-Acid ............................................................................. 4 Nickel-Cadmium ......
Air Starting Motor ................................................................. 17 Cranking Time Required .................................................. 17 Air Consumption of the Starter Motor ............................ 17 Operation ........................................................................... 18 Starting Motor Torque Calculation ................................. 18 Prelubrication Systems .................................................... 18 Piping ................................
Foreword C-9 C9 C-10/C-12 C11/C13 C-15/C-16 C15/C18 3412E C27/C32 3500 C175 3600 G3300/G3400 G3500 G3600 Electric Starter Pneumatic Starter Pneumatic Starter with Prelubrication Hydraulic Starter C7 l Standard m Optional - Not Available 3126B This section of the Application and Installation Guide generally describes Starting Systems for Cat® engines listed on the cover of this section.
Starting Systems Application and Installation Guide Starting Systems An engine starting system must be able to crank the engine at sufficient speed for fuel combustion to begin normal firing of the cylinders and keep the engine running. Startability of an engine is affected by factors such as ambient temperature, engine jacket water temperature, and lubricating oil viscosity. In addition, parasitic loads, usually associated with the driven equipment, can greatly influence the startability.
Application and Installation Guide Starting Systems Starter Types There are three types of starting systems normally used for Cat engines. They differ in the method of storing and recharging the energy required for restarting the engine. Electric Starting Systems Electrical systems use chemical energy stored in batteries. The batteries are automatically recharged by an engine-driven alternator or by an external source.
Starting Systems Application and Installation Guide Electric Starting Electric starting is the most convenient starting system to use. Batterypowered electric motors utilize low voltage direct current and provide fast, convenient, push-button starting with lightweight, compact, enginemounted components. A motor contactor isolates the control logic circuits from high cranking currents. Storage of energy is compact; however, charging the system is slow and may make starting difficult in case of emergency.
Application and Installation Guide Starting Systems solenoid in an up position. This would provide drainage and prevent water from collecting in the solenoid. Engines that are subject to heavy driven load during cold start-up should be provided with a heavy-duty starting motor. See section on Driven Load Reduction Devices. Note: Marine and Petroleum engines use separate ground starters and alternators. See section for further information.
Starting Systems Application and Installation Guide Group Size Accessible Non-accessible 8D 101-4000 153-5720 4D 9X-9730 153-5710 4D 9X-9720 153-5700 31 115-2422 & 115-2421 9X-3404 Maintaining Accessible Batteries Accessible batteries require periodic checks for proper electrolyte level. The electrolyte level should be covering the plates/grids (½ inch (13mm)) within the battery to maximize full charge transfer.
Application and Installation Guide Starting Systems Temperature vs. Output °F (°C) % 80°F Ampere Hours Output Rating 80 (27) 100 32 (0) 65 0 (-18) 40 Table 2 Battery Location and Hydrogen Venting Battery compartments should be configured to allow easy visual inspection for terminal corrosion and damage. Install batteries in well-ventilated compartments only. Batteries emit hydrogen gas during the recharging cycle. Hydrogen gas is highly explosive and very dangerous, even in small concentrations.
Starting Systems Application and Installation Guide generator sets are subject to long idle periods or many short stop-start cycles, insufficient battery capacity could threaten dependability. Optimum charging volts for 12-volt battery vs. temperature for lead acid batteries, utilizing a charger. *Use Caterpillar Data Sheet, PEHJ-0073 to identify chemical construction of Caterpillar batteries to determine recommended charging voltages in previous table.
Application and Installation Guide Starting Systems Starter Motor Cooling Period Between Cranking Periods Allow the starter motor to cool for two minutes before resuming cranking. If Marine Society certified, refer to applicable documents for cranking requirements. Starting System Wiring Power carrying capability and serviceability are primary concerns of the wiring system.
Starting Systems Application and Installation Guide Battery Cable Sizing (Maximum Allowable Resistance) The start circuit between battery and starting motor, and the control circuit between the battery, battery-switch, and motor solenoid must be within maximum resistance limits shown in Table 3. Note: Resistance values in Table 3 include connections and contactors, except the motor solenoid contactor.
Application and Installation Guide Starting Systems Figure 3 Maximum Recommended Total Battery Cable Length Cable Size Direct Electric Starting 12 Volt 24 – 32 Volt AWG MM2 Feet Meters Feet Meters 0 50 4.0 1.22 15.0 4.57 00 70 5.0 1.52 18.0 5.49 000 95 6.0 1.83 21.0 6.40 0000 120 7.5 2.29 27.0 8.24 Table 4 To meet cable length and resistance requirements, cable size is most important.
Starting Systems Application and Installation Guide Figure 4 Connections/Proper Practices Electrical connections are often a source of problems in any application. Shipboard, drill rig and any other electrical system that is exposed to salt air and water are especially susceptible because these elements are highly corrosive. Electrical connections are usually made of dissimilar metals. Corrosion is more destructive between dissimilar metals.
Application and Installation Guide Starting Systems (0.012 milliamps) requirement. For marine systems that have critically high leakage current monitoring; a ground/negative side relay will need to be installed to prevent fault monitoring systems from activating. This is a builder, operator specified feature and is not a standard requirement. Figure 7 a simple circuit showing a suggested method to connect this negative isolation relay to disconnect the high current negative circuit for the starter.
Starting Systems Application and Installation Guide Sample Wiring Diagrams DC Dual Starting System Figure 5 ©2016 Caterpillar All rights reserved.
Application and Installation Guide Starting Systems Typical Wiring Systems Figure 6 Figure 7 Page 14 ©2016 Caterpillar All rights reserved.
Starting Systems Application and Installation Guide Pneumatic Starting (Air) Air starting, either manual or automatic, is highly reliable. Torque available from air motors accelerates the engine to twice the cranking speed in about half the time required by electric starters. Pneumatic starting is generally applied to large engines in work-boats, on land where facilities have existing plant air, or where a combustible gases may be present in the atmosphere.
Application and Installation Guide Starting Systems Air Tank Air tanks are required to meet specific characteristics, such as the specifications of the American Society of Mechanical Engineers (ASME). Compressed air storage tanks must be equipped with a maximum pressure valve and a pressure gauge. Check the maximum pressure valve and pressure gauge often to confirm proper operation. A drain cock must be provided in the lowest part of the air receiver tank for draining condensation.
Starting Systems Application and Installation Guide Example: A 3516 Diesel Engine with electric prelube has the following: Maximum air tank pressure = 1241 kPag (180 psig) Minimum air to starter pressure = 620.5 kPag (90 psig) Expected air line pressure drop = 207 kPag (30 psig) Six consecutive starts. First start = 7 seconds the other 5 starts = 2 seconds Average barometric pressure at this location = 100 kPa (14.5 psi) Preconditioned engine installation. (cfm x 0.02832 = m3/min) Solution: VS = 0.
Application and Installation Guide Starting Systems Operation The supply of compressed air to the starting motor must be shut off as soon as the engine starts. This will prevent wasting starting air pressure and prevent damage to starter motor by over-speeding. Starting Motor Torque Calculation It is important when selecting the starting motor to ensure the motor produces enough torque to overcome the breakaway and rolling torque of both the engine and driven equipment.
Starting Systems Application and Installation Guide Caterpillar furnishes an air cranking/air prelubricating system. This consists of an air-driven prelubrication pump that draws oil from the engine sump and forces it into the engine. This pump is driven by an air motor, through sequence valving runs, until a predetermined engine oil pressure shuts it off and turns on the air cranking motor.
Application and Installation Guide Starting Systems Starter/prelube supply and exhaust piping practice is critical when installing the engine. If restricted in excess the starter motor performance will be negatively impacted. Proper pipe diameter, length and directional changes such as elbows, tees and the like, all must be accounted for in the piping design.
Starting Systems Application and Installation Guide 3516 Oil-Field Engine with Optional Air Starter and Air Prelubrication Figure 9 ©2016 Caterpillar All rights reserved.
Application and Installation Guide Starting Systems Typical Air Starting System Figure 10 Page 22 ©2016 Caterpillar All rights reserved.
Starting Systems Application and Installation Guide Figure 11 ©2016 Caterpillar All rights reserved.
Application and Installation Guide Starting Systems Figure 12 Page 24 ©2016 Caterpillar All rights reserved.
Starting Systems Application and Installation Guide Hydraulic Starting Hydraulic starting provides high cranking speeds fast starts, and is relatively compact. Recharging time, using the small engine-driven recharging pump, is fast. Hydraulic systems can be recharged using a special hand pump, but process is very laborious. The high pressure of the system requires special pipes and fittings and extremely tight connections.
Application and Installation Guide Starting Systems Starting Aids Diesel engines require the heat of compressed air in the cylinder to ignite the fuel. Below certain temperatures, the cranking system will not crank the engine fast enough or long enough to ignite the fuel. One or more commonly used starting aids, such as jacket water heaters and/or ether may be required to start the engine. In addition, engines with prelube requirements may require oil heaters.
Starting Systems Application and Installation Guide CAUTION: Under no circumstances should ether be used on any 3600 model engines or any engine that has an air inlet heater. Warning labels may be necessary if remote air intakes are used and the engine has an inlet heater. Labeling when remote air inlets are used is the responsibility of the customer or end user.
Application and Installation Guide Starting Systems Some engine driven air compressors provide for shutoff of the air compressor air inlet during cold starting. This greatly decreases drag on the engine and improves cold startability. This approach can only be used when the air compressor manufacturer provides this system and fully approves of its use. Air compressor damage could result. Page 28 ©2016 Caterpillar All rights reserved.
Starting Systems Application and Installation Guide Emergency & Fast Starting Some emergency and standby power applications require the ability for fast starting. Certain engine configurations are capable of supporting emergency power supply systems such that loads can be accepted within 10 seconds of a power outage. The following list offers recommendations to achieve faster starting.
Application and Installation Guide • • • • • • • Starting Systems Some gas gensets are designed specifically for standby applications. Gas trains provided with these gensets should be installed as supplied with the gas train components and flexible hose installed directly to the engine fuel inlet. This ensures fastest starting capability. The fuel shutoff valve must be energized at the same time as the s tarters. High-pressure gas systems will reach high idle faster than lowpressure gas systems.
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