The Fluke high-voltage digital megohmmeter is an insulation tester with preset and adjustable test voltages for measuring insulation resistance to 1TΩ (2TΩ for 10kV models) to indicate the condition of windings or cables in motors, switchgears, electrical installations, and other insulated equipment, and it also measures leakage current to 2 milliamperes (mA), capacitance to 20μF, and AC and DC voltage to 600V, signaling when a voltage greater than 30V is detected. In addition to the preset test voltages of 250V, 500V, 1,000V, 2,500V, 5,000V, plus 10,000V for the 10kV models, test voltages can be adjusted in 50V increments to 1,000V and 100V increments above 1,000V. Its PI/DAR (polarization index/dielectric absorption rate) function automatically calculates PI and DAR, which are measurements over time that give a truer indication of insulation condition than single-point measurements. The meter can perform timed tests up to 99 minutes, adjustable in 1-minute increments, and has storage for up to 99 test results. Stored results can be uploaded to a PC with the included FlukeView Forms Basic software. The software is compatible with Microsoft Windows 2000, XP, and Vista. For improved accuracy during high-resistance testing, the guard terminal eliminates interference from leakage current. The meter has an LCD that shows the reading numerically and in a bar graph. Megohmmeters are commonly used for electrical maintenance and testing in industries such as HVAC, transportation, manufacturing, mining, and utilities, among others.
The meter is rated for category (CAT) IV installations to 600V, which covers equipment at the origin of the installation, such as electricity meters and primary over-current protection equipment, and CAT III installations to 1,000V, which covers equipment in fixed installations, such as switches in the fixed installation and some industrial equipment that is permanently connected to the fixed installation. The unit has a low-battery indicator that signals when the battery needs to be replaced and automatically turns off after 30 minutes of non-use. It comes with a set of test cables with alligator clips, a set of heavy duty alligator clips (for kit and 10kV models), an infrared-to-USB interface cable, FlukeView Forms Basic CD-ROM, rechargeable 12V lead-acid battery (installed), an AC power cord for charging the battery, instructions, a soft carrying case (only for models without kit), a hard carrying case (only for kit models), and a certificate of calibration (only for kit models).
|Maximum insulation resistance measured||1TΩ for Fluke 1550C; 2TΩ for Fluke 1555|
|Test voltages||250V, 500V, 1,000V, 2,500V, 5,000V; also 10,000V for Fluke 1555|
|Maximum leakage current measured||2mA|
|Maximum capacitance measured||20μF|
|Maximum AC and DC voltage measured||600V|
|Installation rating||CAT IV, 600V; CAT III, 1,000V|
|Standards met||EN safety standards 61010-1 and 61557; CE marking; CSA and TÜV certification|
|Power||Rechargeable 12V lead-acid battery|
|Dimensions (H x W x D)*||170 x 242 x 330mm/6.7 x 9.5 x 13 inches|
*H is height, the vertical distance from the lowest to highest point; W is width, the horizontal distance from left to right; D is depth, the horizontal distance from front to back.
Megohmmeters, also called insulation testers, are electrical test meters that measure resistance to the flow of current in an electrical component or circuit and check the continuity of an electrical circuit to detect electrical problems such as degraded insulation and improper circuit connections in equipment, wiring, and power supplies. Resistance is an indicator of the overall condition of the device being tested. Megohmmeters have an internal power supply, such as a battery or a capacitor, which supplies a test voltage to a circuit or component that is turned off. Test leads are connected in a series to the tester and the circuit or device being tested. The meter calculates the difference in voltage between the leads and measures the resistance. Most megohmmeters have two terminals for test lead attachment. The two-terminal, or two-wire, measurement method includes the resistance of the circuit or device being tested and the resistance of the test leads, and generally provides sufficient accuracy for measuring large values of resistance in insulation testing applications.
Fluke Corporation manufactures electrical testing tools and software for industrial and commercial applications. The company, founded in 1948, is headquartered in Everett, WA.