ADDITIONAL SIGNAL SUPPORT EQUIPMENT CHECKS DURING

OPERATIONS

2-62. The following are basic checks and balances that should be performed once the unit is executing the mission.

2-63. Power, grounding, and power distribution are extremely important to signal planning. Approximately fifty percent of all communications outages are attributed to power failures. Key components to power planning are the selection of a power source, set- up of power generators, grounding of power sources and electrical components, and distribution and extension of power.

Note. Power (symbol P) is defined by units called watts (W).

Current (symbol I) is defined by units called an ampere (amp or A). Voltage or the potential difference (symbol E) is defined by units called volts.

Power = (Current) x (voltage) or P = IE or P = I (voltage)

G

,C

B

,

P

S

2-64. Signal Soldiers are often signed for or responsible for unit generators. The right generator, circuit breaker, and power source will ensure signal equipment functions properly. Before a power source is selected, separate signal equipment from air conditioners, refrigerators, microwaves, heaters, coffee pots, etc. Air conditioners have compressors, and for most models, the compressor only engages periodically. Each time the compressor engages, the power draw increases, creating fluctuation in the current available. Current fluctuations cause electronic devices to react abnormally and failure is more likely to occur.

2-65. Circuit breakers need to be rated for the circuit requirements. For example, a 20 amp circuit breaker on a 110 volt circuit provides P = (110) (20) W = 2200 W or 2.2 kilowatts (Kw).

2-66. Generators must be set up properly and be matched to the task. Generators normally operate with one, two, or three phases, and should be loaded to 80 percent of capacity when possible. Loads should be distributed to all phases of the generator.

2-67. Phases of the generator divide the available power rating by the number of phases. For example, a single-phase 10 Kw generator provides P = IV, 10 Kw = (110) (I) or I = 10 Kw/110 volts = 90 amps. A three phase 15 Kw generator provides 5 Kw on each circuit or 5 Kw/110 volts = 45amps. Therefore, if a 50-amp circuit is required, a single-phase 10 Kw generator is better than a three phase 15 Kw generator. Bigger is not always better when taking all of these factors

2-68. Power generators require level ground and proper grounding. Power sources are especially susceptible to faults when electrical grounds do not meet to standards. Generators typically have 9-foot copper ground rods with copper grounding cables that should be used at all times. Ensure they are checked (less than 25 ohms of resistance) after installation. Use ground test meters every time to ensure proper ground before operation. Use salt and water, add ground rods and link them together with copper cable until the requirement is met; less resistance is better. Never ground a power source together with a signal entry panel or any signal equipment. Power sources and power feeders should always remain separate.

2-69. Power generators play an important role for signal leaders. The following steps are equally important, whether using commercial or tactical generators. Ensure the following steps are being preformed to keep generators working properly during operations—

z Paralleling generators and using switch boxes can be essential to a power plan for communications equipment. Generators must be cabled properly, and the switch box must be rated to perform the job. Even in the best situation, a power spike or failure may occur if the system is not set up right.

z Ensure power generators are in good working order and track hours operated by using the hour meter or by keeping a logbook, and perform preventative checks and services before, during, and after operations.

z Use clean, uncontaminated fuel.

z Replace air and oil filters regularly and more often in austere

environments. Most generators must be off line to change filters. Sandy environments can cause air filters to clog quicker than normal so replace or clean them more often when necessary.

z Generators must be kept as cool as possible. Sun loading (sun

shining directly on a generator) can cause overheating. Shading a generator with sunshades or camouflage can keep the temperature within the normal operating range even if the ambient temperature is high.

z During operations, it is important to watch the loading of generators. Usage can also cause the load to become unbalanced.

z Ensure all Soldiers know how to use a multimeter on all assigned equipment. They are essential for signal equipment and can make the difference between a piece of equipment staying in good condition or always having to be repaired. Another useful tool is a plug-in polarity checker (which can be found at most electrical shops). The polarity checker has light emitting diode readouts that provide information about the source of power.

z Ensure that all operators are proficient in cutover emergency procedures.

2-70. It is important for signal leaders to know what power is available at all plug-in points being used. Most equipment comes with a power cord and the cord is rated to provide the needed electricity to the electronic components from the origination source.

2-71. If the length of the provided power cable is being extended by using extension cords or other cables, measure the power available at the source of the last plug, or calculate the power loss for the cable and ensure the original source can provide what is needed over the distance of the extension. The gauge of the cable or the loss rating will need to be known.

2-72. An uninterruptible power supply (UPS) at the end of an extension cord cannot recharge if it is not provided enough power. If the UPS is getting just enough power to provide power to the components it services, when back-up power is needed the UPS will fail. Soldiers must measure the power into the UPS and ensure it has the capacity to provide failsafe power to the components it is responsible for protecting. In the wrong configuration, the UPS may inhibit the components from working properly by taking power from the source. Even a fully charged UPS may steal power from the circuit over time.

Chapter 3