CONNECTION AT THE MOTORS
Steelman KVAR capacitors may be connected such that they are switched with the motor. By utilizing this type of connection, as shown in Figures 1 & 2, maximum benefit of power factor correction is obtained by minimizing system losses. This is because the distribution system will be carrying less current down to the point of connection of the KVAR capacitor. In addition, no individual disconnect switch is required to meet National Electric Code (NEC) requirements.
MOTOR INSTALLATION LOCATION
Figures 1 & 2, show the recommended electrical locations for connection of KVAR Units to individual motors. Special care must be exercised when connected as in Figure 2. The overload relay heater coils must be resized due to the reduction in current through the overloads. The best procedure in resizing the heater coils is to take an amp meter reading on the line side of the overload relay after correction under operating conditions. Special motor applications are shown in Figure 4.
KVAR UNIT WIRE SIZING
The minimum wire sizing amperage of the KVAR Unit should be found by multiplying 1.35 times the amperage of the capacitor. The amperages for Steelman KVAR Units are shown in Table 4. In addition, the wire size used should be a minimum of 1/3 the conductor size to the individual motor.
KVAR UNIT INTERNAL FUSES
Steelman KVAR Power Factor Correction Capacitors, contain replaceable internal, high interrupting capacity, fuses as an optional feature. Fuses are used to disconnect capacitor cells in the event of transient voltages, before damage is done to the internal wiring or capacitor itself. These fuses minimize hazard to personnel, property, and adjacent capacitor cells. The internal fusing is not a substitute for a switching device or external protection of the capacitor bank.
KVAR UNIT PILOT LIGHTS
Steelman KVAR Units have an optional pilot light feature for units with internal fuses. A pilot light is a red indicator light that glows when a fuse is blown. This option allows for a visual maintenance inspection of KVAR Unit.
CONNECTION AT THE PANEL
Steelman KVAR Capacitors may be connected at any point within the electrical distribution system provided proper precautions are taken to comply with National Electrical Code and local code requirements. Refer to Article 460 of the National Electrical Code for capacitor installations.
FIXED CAPACITOR DISCONNECT SWITCH
A fused disconnect switch or circuit breaker is required between the KVAR Unit and connection onto the electrical distribution system. Disconnect switches and fuses should be sized for a minimum of 1.65 times the expected capacitor current for dual element fuses or 2.5 times the capacitor current if single element fuses are used. If circuit breakers or contactors are used, they should be sized for 1.5 times the expected capacitor current. Please refer to Figure 3 and Table 4.
INSPECTION & MAINTENANCE
At time of receipt and installation, make sure that the equipment has not been damaged during shipment. Check compliance with local code and manufacturers specifications. Insure suitability of switching, protective devices and connections. An additional inspection should be made within 8 to 24 hours after energizing, and at the first periods of light load situations to insure that voltages and currents are balanced and are within the limits of the capacitor rating. Check to make sure operating KVAR will not exceed 135% of rated current under the most severe operating conditions.
OVER CURRENTS
The first indication of excessive currents may be the failure of fuses and/or capacitor cells, or excessive capacitor temperature rise. Overcurrents may be due to excessive voltage, or harmonic voltages, the chief sources of which are rectifiers, saturated transformer cores, and solid state DC power converters. If harmonic voltages are present in the electrical system, they can cause the failure of fuses and capacitor cells. Capacitors do not cause harmonics. It is the responsibility of the user to provide proper protection of the KVAR Units from harmonics. When this condition is suspected, a harmonic power study may need to be conducted, and harmonic filters installed. See page 12 for more information.
