Section 3

DESCRIPTION & COMPONENTS

The resulting direct current from the BCR is delivered to the 12 VDC receptacle, via Wire 13A, CB1, and Wire 15A. This receptacle allows the capability to recharge a 12 volt DC storage battery with provided battery charge cables.

Insulation Resistance

The insulation resistance of stator and rotor wind- ings is a measurement of the integrity of the insulat- ing materials that separate the electrical windings from the generator steel core. This resistance can degrade over time or due to such contaminants as dust, dirt, oil, grease and especially moisture. In most cases, failures of stator and rotor windings is due to a breakdown in the insulation. In many cases, a low insulation resistance is caused by moisture that collects while the generator is shut down. When problems are caused by moisture buildup on the windings, they can usually be corrected by drying the windings. Cleaning and drying the windings can usu- ally eliminate dirt and moisture built up in the genera- tor windings.

The Megohmmeter

GENERAL:

A megohmmeter, often called a “megger”, consists of a meter calibrated in megohms and a power supply. Use a power supply of 500 volts when testing stators or rotors. DO NOT APPLY VOLTAGE LONGER THAN ONE (1) SECOND.

TESTING STATOR INSULATION:

All parts that might be damaged by the high meg- ger voltages must be disconnected before testing. Isolate all stator leads (Figure 3-9) and connect all of the stator leads together. FOLLOW THE MEGGER MANUFACTURER’S INSTRUCTIONS CAREFULLY.

Use a megger power setting of 500 volts. Connect one megger test lead to the junction of all stator leads, the other test lead to frame ground on the stator can. Read the number of megohms on the meter.

The MINIMUM acceptable megger reading for stators may be calculated using the following formula:

MINIMUM INSULATION

 

GENERATOR RATED VOLTS

 

RESISTANCE

=

__________________________

+1

1000

(in “Megohms”)

 

 

 

 

 

 

 

 

 

EXAMPLE: Generator is rated at 120 volts AC. Divide “120” by “1000” to obtain “0.12”. Then add “1” to obtain “1.12” megohms. Minimum insulation resistance for a 120 VAC stator is 1.12 megohms.

If the stator insulation resistance is less than the cal- culated minimum resistance, clean and dry the stator. Then, repeat the test. If resistance is still low, replace the stator.

Use the Megger to test for shorts between isolated

windings as outlined “Stator Insulation Tests”.

Also test between parallel windings. See “Test Between Windings” on next page.

TESTING ROTOR INSULATION:

Apply a voltage of 500 volts across the rotor positive

(+)slip ring (nearest the rotor bearing), and a clean frame ground (i.e. the rotor shaft). DO NOT EXCEED 500 VOLTS AND DO NOT APPLY VOLTAGE LONGER THAN 1 SECOND. FOLLOW THE MEGGER MANUFACTURER’S INSTRUCTIONS CAREFULLY.

ROTOR MINIMUM INSULATION RESISTANCE:

1.5megohms

* CAUTION: Before attempting to measure

Insulation resistance, first disconnect and Isolate all leads of the winding to be tested. Electronic components, diodes, surge protec- tors, relays, Voltage Regulators, etc., can be destroyed if subjected to high megger volt- ages.

HI-POT TESTER:

A“Hi-Pot” tester is shown in Figure 3-8. The model shown is only one of many that are commercially available. The tester shown is equipped with a voltage selector switch that permits the power supply voltage to be selected. It also mounts a breakdown lamp that will illuminate to indicate an insulation breakdown dur- ing the test.

Figure 3-8. – One Type of Hi-Pot Tester

Stator Insulation Resistance Test

GENERAL:

Units with air-cooled engines are equipped with (a) center tapped AC power windings, (b) an excitation

Page 13

Page 14 Page 16
Page 15
Image 15
Guardian Technologies 5308, 4582 & 4987, 4451 & 4986, 4583 manual Megohmmeter, Stator Insulation Resistance Test
Page 14 Page 16

5308, 4583, 4451 & 4986, 4582 & 4987 specifications

Guardian Technologies has carved a niche in the market with its innovative air purification and UV-C sanitization products. The company's model numbers, including 4582, 4987, 4451, 4986, 4583, and 5308, represent a diverse range of solutions designed to enhance indoor air quality and safety in both residential and commercial settings.

The Guardian Technologies 4582 is equipped with a true HEPA filter that captures 99.97% of dust, pollen, smoke, and other particles as small as 0.3 microns. This model features a smart sensor that adjusts the fan speed according to the air quality in real-time. The UV-C light technology integrated into this device works to eliminate viruses and bacteria, providing an additional layer of protection against airborne pathogens.

The 4987 model follows suit with similar advanced features but adds a sleek design ideal for modern interiors. With multiple speed settings and a night mode, the 4987 is perfect for bedrooms or quiet spaces. Its energy-efficient operation coupled with an indicator that signals filter replacement ensures that users maintain optimal performance effortlessly.

The Guardian Technologies 4451 and 4986 models are particularly notable for their enhanced capacity and filtration efficiency. Both units incorporate a three-in-one filtration system that includes a pre-filter, activated charcoal filter, and HEPA filter. With their strategic design, these models not only purify the air but also trap common household odors, making them a popular choice for families with pets.

The 4583 model stands out with a unique combination of design and functionality. It features a low-profile design, making it easy to fit into any space. Its UV-C light technology not only disinfects air but can also sanitize surfaces, bridging the gap between air purification and direct sanitation.

Finally, the Guardian Technologies 5308 caters to larger spaces, offering impressive air circulation and filtration capabilities. Equipped with a high-efficiency particulate air (HEPA) filter and a powerful fan, it effectively cleans larger areas while maintaining whisper-quiet operation.

In summary, Guardian Technologies’ products exemplify a commitment to improving air quality and promoting health through innovative technology. With features like HEPA filtration, UV-C sanitization, smart sensors, and sleek designs, consumers can choose from a range of models that best fit their needs, ensuring cleaner, safer indoor environments.
Top Page Image Contents