Voltage checking

Increased anode resistance Increase rectifier voltage, check anode bed... 

Allow the pump to run 5 minutes prior to voltage check. 

Low heat input Check heater voltage, check for continuity of elements, burned-out elements, or poor electrical or thermal contact. 

Procedure Fill a beaker two-thirds with salt solution, dip a copper strip to one side of the beaker and magnesium ribbon to the other side. Attach both metals to a multimeter, record the voltages. Check formation of an electric current with a light bulb or an electric motor. Replace magnesium by other metals like zinc or iron, or even with copper record the values measured. 

Select the correct series resistors and adjust the test voltage. Check that satisfactory scintillation is being obtained. Maintain the test condition for 6 hours. 

Process air temperature too low Incorrect temperature setting on-controller Controller malfunctioning Process heating elements Thermostat malfunction Voltage differentials Inadequate air flow Hose connections incorrect Inadequate insulation Dryer inadequate for required temperatures Reset for correct temperature Check electrical connections. Replace/repair if needed Check electrical connections Replace/repair if needed Replace or repair Check supply voltage Check/clean filters, check blower rotation and correct, check and repair air flow meter Check connections. Delivery hose should enter hopper at bottom Insulate hopper and hopper inelt air line Replace with high temperature dryer... 

Motor runs too slow Low armature voltage Check for resistance in armature circuit... 

Starter operating) Wrong supply voltage Check name plate against supply... 

Equipment Voltage Check by user Recorded visual inspection Recorded Inspection and test... 

Checks on the internal electronics, such as verifying that the voltage levels of internal power supplies are within specifications. 

The bearing insulation is thus determined by the manufacturer while checking the shaft voltage at the works. This forms a routine in-house test for all HT and large LT motors. 

This check may be carried out both at the works, after final assembly, and at the site after the installation before conducting routine tests or energizing the assembly. The ehecks can be carried out at a lower voltage to detect any shorting links or spanners left inadvertently on live terminals, weak insulation or insufficient clearance or creepage distances between the phases or phase to ground conduetors. In the ease of a defect the same must be rectified immediately. 

Wet test While an indoor type switchgear assembly requires only a dry power frequency voltage withstand test, the outdoor type switchgear assembly also needs a wet test under wet conditions to check the external insulation. For the test procedure refer to lEC 60060-1. 

Checking for the grounding of instrument transformers by means of a low-voltage source (10 V or so) using a bell, buzzer or a light. 

Polarity test to check the connections through the potential transformer to ensure that the connections between the transformer and the meters or relays have a correct relative polarity. Otherwise the meters would show erratic readings, while the relays would transmit wrong signals. This test may also be conducted with a low-voltage source of 10 V by ob.serving the deflection of the instruments. 

To check the terminal voltage and frequency Figure 16.28 suggests a simple method to measure the terminal voltage and the frequency / of the incoming machine ... 

This is a simpler method to check the phase displacement between the incoming and the existing voltage. Normally two lamps are connected in series to make them suitable for 480 V as shown to withstand the maximum line voltage, in case the two voltages fall 180° apart. This voltage, AV can rise to... 

From the reproduced protective characteristics of this arrester, as in Table 18.11, the nearest next higher rating available is 336 kV for a 420 kV system voltage. This is the basic rating of the arrester which must be further checked for... 

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