What is a megohmmeter?
A megohmmeter is a specialized type of multimeter that is used specifically for insulation testing. It measures the electrical resistance of a material, and is usually used to test the insulation of electrical wires.
Megohmmeters are typically used in industrial applications, such as testing the insulation of electrical equipment. They are also sometimes used in home wiring applications.
How do megohmmeters work?
The working principle of a megohmmeter is very simple. Megohmmeters work by sending a small current through the material being tested. If there are very high resistance values, like motor windings and other inductive loads.You can send the same current on different voltage levels, depending upon the sensitivity.
The megohmmeter then measures the voltage drop across the terminals. After that, it calculates the resistance of the material based on the voltage drop. Moreover, megohmmeters can also measure the inductance of a material.
What is a multimeter?
A multimeter is a versatile tool that can be used for a variety of electrical measurements. It can measure voltage, current, and resistance. Moreover, a multimeter can also be used to measure AC Voltage, DC Voltage, AC Current, DC Current, capacitance, inductance, and temperature.
Multimeters are typically used in a variety of applications, such as troubleshooting electrical equipment and testing batteries. They can combines multiple functions and give you results with high accuracy.
How do multimeters work?
You have to select a specific function on the multimeter, such as voltage or current. You can test voltage or measure current of all electrical equipment with a standard multimeter. All you have to do is to attach the probes of the multimeter to the test terminals.
Incase of an insulation test, all you have to do is to select the Resistance function. Then touch the probes to the both end terminals. So, The multimeter will then display a reading on the screen. This reading will tell you the resistance of any inductor or wire.
Differences between megohmmeters and multimeters
Megohmmeter vs multimeter: The main difference between megohmmeters and multimeters is that megohmmeters are specifically designed for insulation testing, while multimeters are versatile tools that can be used for a variety of electrical measurements.
Additionally, megohmmeters are typically used in industrial applications, while multimeters are more commonly used in home wiring applications. Furthermore, megohmmeters can measure the capacitance and inductance of a material, while multimeters can measure almost every electrical variable.
When would you use a megohmmeter vs when would you use a multimeter?
The megohmmeter is the best tool for insulation testing, while the multimeter is the best tool for general electrical measurements. If you need to measure the capacitance or inductance of a material, then you should use a megohmmeter.
If you need a general purpose tool for both electrical and electronics work then multimeters are more suited. Moreover, electrical resistance of bigger windings like Transformers, motors and cables is very high. Therefore measuring resistance of these conductors is a bit difficult with a multimeter.
Pros and Cons (Megohmmeter vs multimeter)
Megohmmeters:
Pros- Megohmmeter is specifically designed for insulation testing.
- It is very easy to use.
- Megohmmeters can measure the capacitance and inductance of a material.
- Megohmmeter has a relatively higher CAT rating.
- A Megohmmeter is an electronic measuring instrument and more sensitive. Therefore, calibration is required after a couple of weeks.
Multimeters:
Pros- A Multimeter is an all in one tool.
- Compact in size so they are easy to carry.
- Longer Battery life.
- It is highly affordable and easy to use.
- Using them improperly can cause their calibration to be incorrect.
Buying Guide for Megohmmeters and Multimeters
Megohmmeter vs multimeter: When it comes to electrical testing and troubleshooting, two essential tools are megohmmeters and multimeters. These instruments are crucial for professionals in the electrical, electronics, and maintenance fields. This guide will help you understand the key features and considerations when purchasing a megohmmeter or a multimeter, ensuring you make an informed decision.
Understanding Megohmmeters and Multimeters
Megohmmeters are specialized instruments used to measure the electrical resistance of insulators. They apply a high voltage to the insulation material and measure the resulting resistance, which is typically in megohms (MΩ). These tools are vital for testing the insulation resistance of wires, cables, transformers, and other electrical components to ensure safety and efficiency.
Multimeters, on the other hand, are versatile instruments that measure various electrical parameters, including voltage (AC/DC), current (AC/DC), and resistance. Some advanced models also measure capacitance, frequency, temperature, and more. They are essential for diagnosing electrical issues, performing repairs, and conducting routine maintenance.
Key Features to Consider
For Megohmmeters:
Voltage Range:
Megohmmeters come with different test voltage ranges, typically from 250V to 5kV or higher. The voltage range you need depends on the applications you will be testing. Higher voltages are required for testing high-voltage equipment.
Resistance Range:
The resistance measurement range is another critical factor. Ensure the megohmmeter can measure the resistance values you expect in your applications, usually from a few megohms to several gigohms.
Accuracy:
Look for a megohmmeter with high accuracy to ensure reliable measurements. Accuracy is often specified as a percentage of the reading, so check the specifications carefully.
Durability and Safety:
Megohmmeters should be rugged and durable to withstand harsh environments. Safety features like CAT ratings (Category ratings) indicate the meter’s ability to handle transient voltages safely.
Additional Features:
Some megohmmeters offer additional features such as polarization index (PI) and dielectric absorption ratio (DAR) measurements, which provide more insights into the insulation quality.
For Multimeters:
Measurement Capabilities:
Ensure the multimeter can measure all the parameters you need. Basic models measure voltage, current, and resistance, while advanced models include additional functions like capacitance, frequency, temperature, and diode testing.
Auto-ranging vs. Manual-ranging:
Auto-ranging multimeters automatically select the appropriate range for the measurement, making them easier to use. Manual-ranging multimeters require you to set the range, which can be more precise but less convenient.
Display:
Look for a multimeter with a clear, easy-to-read display. Backlit displays are useful in low-light conditions. The display count, which indicates the maximum value the display can show, is also important.
Accuracy and Resolution:
Higher accuracy and resolution mean more precise measurements. Accuracy is usually expressed as a percentage of the reading, and resolution is the smallest change the meter can detect.
Safety Features:
Safety is paramount when working with electrical equipment. Look for multimeters with appropriate CAT ratings for your applications. Additional safety features like overload protection and fused inputs are also important.
Durability:
A robust, durable multimeter will last longer and perform better in challenging environments. Consider models with protective cases and rugged construction.
Conclusion: Megohmmeter vs multimeter
Megohmmeter vs multimeter: If you need to measure the inductance, resistance, and continuity of a wire, then you should use a megohmmeter. But for those who are looking for a professional all in one tool, a multimeter is the best option. I have also made a list of the best multimeters for electricians also.
Moreover, if you’re on a budget then you can also visit the best budget multimeters list. Hopefully this multimeter vs megohmmeter comparison helps you in choosing the right one.
FAQs- Frequently Asked Questions
Can a multimeter be used as a megohmmeter?
To an extent you can use a multimeter instead of a megohmmeter, but it is not recommended. Because megohmmeters are specifically designed for insulation testing, while multimeters are more of a general purpose tool.
Although multimeters have resistance testing options, it’s for small components. Moreover, megohmmeters pass high voltage through conductors to check their insulation. Therefore, it’s better to use a megohmmeter for insulation testing.
Is an insulation tester the same as a multimeter?
No, an insulation tester is not the same as a multimeter. An insulation tester is specifically designed for testing the insulation of electrical equipment. But multimeters are for all electrical measurements.
Can you measure insulation resistance with a multimeter?
Yes you can do an insulation test with a multimeter. Because for insulation testing you need to measure the resistance. But its accuracy would not be as good as megohmmeter.
How does a megger differ from an ohm meter?
An ohmmeter is used to measure the resistance of a circuit, whereas a megger is used to measure the insulation resistance of a circuit. Additionally, an ohmmeter measures the DC resistance of a circuit, while a megger can measure both the AC and DC resistance of a circuit. Megohmmeters measure extremely high resistances by injecting high voltage signal in different inductors, windings and transformers.
