Yokogawa MY40-01 Digital Megohmmeter, 125/250/500/1,000V Test Voltages, 2,000 Megohms Insulation Resistance

The Yokogawa MY40-01 digital megohmmeter is an insulation tester with four test voltages—125, 250, 500, and 1,000V—for measuring insulation resistance to 2,000 megohms to indicate the condition of windings or cables in motors, switchgears, electrical installations, and other insulated equipment, and it also measures low-resistance to 400Ω and AC voltage to 600V, lighting a warning indicator and sounding a buzzer when a voltage greater than 40V is detected. The meter sounds a continuity buzzer at less than 40Ω to confirm that the circuit conducts electricity. A comparator function allows a reference value to be set, compares subsequent readings to that value, and triggers a buzzer and lights a "low" indicator when readings fall below the set value. The memory function stores up to 20 readings. To aid documentation of readings, the data hold function keeps the most recent reading on the display for five seconds after the measure switch is turned off. When measurement is complete and the measure switch is turned off, residual voltage is automatically discharged from the circuit under test. The measure switch can be locked for extended measurement sessions. The meter has a 4,000-count LCD that shows readings numerically and in a bar graph, and has a backlight for visibility in low light. It automatically turns off after ten minutes of non-use to conserve battery life and has a low-battery indicator that signals when the batteries need to be replaced. It is rated for category (CAT) III installations to 600V, 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. It comes with a line probe, an earth probe, a display cover, a shoulder strap, four AA batteries, and instructions. Megohmmeters are commonly used for electrical maintenance and testing in industries such as HVAC, transportation, manufacturing, mining, and utilities, among others.

Specifications

*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.

Yokogawa manufactures test and measurement equipment, navigation systems, and industrial control systems. The company, founded in 1915 in Tokyo, Japan, has U.S. headquarters in Sugar Land, TX. It meets International Organization for Standardization (ISO) standard 9001:2008.

What's in the Box?

• Yokogawa MY40-01 digital megohmmeter
• Line probe
• Earth probe
• Display cover
• Shoulder strap
• (4) AA batteries
• Instructions