Vector Power City DK080706 Owner's Manual & Warranty

Contents

Vector Power City DK080706 Owner's Manual & Warranty Manual pdf 8 page image

84.2 PRINCIPLES OF OPERATIONThe power inverter converts power in two stages. The first stage is a DC-to-DC conversionprocess that raises the low voltage DC at the inverter input to 145 volts DC. The second stageis the actual inverter stage that converts the high voltage DC into 120 volts, 60 Hz AC, Modi-fied Sine Wave (MSW). MSW is a waveform that has characteristics similar to the sine waveshape of utility power. This type of waveform is suitable for most AC loads, including linear andswitching power supplies used in electronic equipment, transformers, and motors. The modifiedsine wave produced by the power inverter has an RMS (root mean square) voltage of 120volts, which is the same as standard household power. Most AC voltmeters (both digital andanalog) are calibrated for RMS voltage under the assumption that the waveform measured willbe a pure sine wave. These meters will NOT READ the RMS voltage of a modified sine wavecorrectly. They will read about 20 to 30 volts low when measuring the output of the power inverter.For accurate measurement of the output voltage of this unit, use a voltmeter marked “TRUE RMS”.Figure 5 compares a Modified Sine Wave with a True Sine Wave.FIGURE 5The Power Inverter is incorporated into the Power City main unit. It’s DC source is the main unit’s12 volt, 19AH battery. Power is provided to the inverter through two flat contacts on the bottomof the inverter. The inverter operates on stored energy in the main battery. With a full charge onthe main battery, the inverter will supply a load of 100 watts for approximately one hour and 5minutes. Lower wattage loads will operate longer, higher wattage loads will operate for a shortertime using energy from the main battery.When the inverter is operated away from the main unit, the power source must providebetween 11 and 14.5 volts DC and must be able to supply the necessary current (amps) to operatethe load. The power source may be a battery or a well-regulated DC power supply. To obtain arough estimate of the current (in amperes) that the power source must deliver, simply divide thepower consumption of the load (in watts AC) by 10.Example: If a load is rated at 100 watts AC, the power source must be able to deliver:100 / 10 = 10 amperesCAUTION: The inverter must be connected only to batteries with a nominal output voltage of12 volts. The unit will not operate from a 6 volt battery and will sustain permanentdamage if connected to a 24 volt battery.The inverter may be used whether or not the vehicle’s engine is running. However, the invertermay not operate while the engine is starting since the battery voltage can drop substantiallyduring engine cranking. The inverter draws less than 0.06 ampere from the battery when it isnot supplying power to a load.4.3 CONNECTING INVERTER TO POWER SOURCE AWAY FROM MAIN UNITThe Inverter can be used away from the main unit by removing it from it’s mounting on themain unit and powering it from the Inverter power cable, located in the storage compartmentin the back of unit. The power inverter has two flat metal contacts that normally mate with theconnector on the main unit. These flat contacts are connected to the inverter power cable (blackand red color) when the inverter is removed from the unit and operated away from the unit. Theinverter power cable comes equipped with a 12 volt DC plug. The tip of the plug is positive andthe side contact is negative. Connect the power inverter to the power source by inserting the DCplug firmly into the accessory outlet of a vehicle or other DC power source. The connection tothe accessory outlet can be improved by slightly rotating the plug in the socket. (See Figures 6and 7)