How to Insert a Relay in Inverter Input Power Supply Line

When I want to electrically disconnect I/O, is it acceptable to insert a relay in the Inverter input power supply line?

From a safety standpoint in case of an internal inverter failure, install a circuit breaker or magnetic contactor in the Inverter's input power supply line, and install a circuit to disconnect the inputs and outputs.

Boost Voltage from 100 VAC to 200 VAC

We are running a three-phase 200 VAC induction motor on single-phase 100 VAC. Are there any Inverters with a function that boosts voltage from 100 VAC to 200 VAC?

There are 3G3EV Inverters that can accept a single-phase 100 VAC input. These models have built-in circuit that boosts the voltage from 100 VAC to 200 VAC.

Settings to Move an Inverter where Power Supply Frequency in New Location is Different

I am moving an Inverter from a location with a 50 Hz power supply frequency to another location with a 60 Hz power supply frequency. Are there any settings that need to be changed?

One of the features of the Inverter is that it will control operation at the same speed regardless of the power supply frequency.

The Inverter initially converts the input power supply to DC and then converts from the DC power supply back to AC, so differences in the power supply frequency have no effect on operation.

Motor Capacity Factor in Selecting an Inverter

Is it necessary to select an Inverter with a capacity that is one class higher than the capacity of the motor being used?

OMRON Inverters use an oversized power module that can output 200% of the motor's rated output, so it is not necessary to select an that is one class higher.

On the other hand, there are some cases in which it is better to select an that is one class higher, even if an OMRON is being selected.

Examples:

• Applications with a large amount of regeneration
• Applications operating continuously with high torque at low speed (such as a load moving slowly on a vertical axis)

Reason of Inverter Set Value is Reverted Back to 1

I changed the set value of Inverter parameter number n01 to 9 (3-wire sequence), as described in the manual, but the setting changed to 1. Why did it change?

A setting of 9 causes the Inverter to be initialized in 3-wire sequence mode. When the setting is changed to 9 and the Return Key is pressed, the Inverter is immediately initialized. At this point, the n01 setting is also initialized and reverts to its default setting of 1.

The same phenomenon occurs if the setting is changed to 8.

Think of parameter n01 as a command that initializes the other parameters. Because it is a command, it does not retain its setting like a parameter.

It is normal for n01 to revert to a setting of 1 after initialization.

Inverter Input and Output Noise Filter

There are two kinds of noise filters available as Inverter accessories: the input noise filter and output noise filter. How are these filters used?

The "Input" and "Output" means that these Inverter Noise Filters are connected to the Inverter's input side and output side.

Input Noise Filter:

Reduces noise escaping to the power supply line.

This filter influences the devices connected to the same AC power supply system.

Output Noise Filter

This filter can suppress noise emitted from the power cable between the motor and Inverter as well as ground noise due to the leakage current from the motor.

This filter influences devices with wiring near the Inverter as well as devices that use the same ground.

The difference between these filters is their different applications.

For example, the Input Noise Filter influences the operation of Sensors such as 2-wire AC Proximity Sensors.

Signal Cannot be Input during Keying in Multi-step Speed Command

I want to input the multi-step speed command in the Multi-function Input Selection parameter, but Err (error) is displayed and the signal can't be input. What is the cause of the problem and the solution?

Err (error) will be displayed and it won't be possible to input the signal if you attempt to input a setting that was already set with another Multi-function Input selector.

For example, when a multi-step speed command is being used in a 3G3JV Inverter and you attempt to set n37 (Multi-function Input 2 selector) to 6 (multi-step speed command 1), Err (error) will be displayed and it won't be possible to input the signal.

This error occurred because n39 (Multi-function Input 4 selector) is set to its default setting of 6, and this setting was duplicated.

Set n37 (Multi-function Input 2 selector) to 6 after setting another value in n39 (Multi-function Input 4 selector).

Can I Control Single-phase Motor with Inverter with Single-phase 100V Input?

Can a single-phase motor be controlled by a 3G3EV Inverter with a single-phase 100-V input?

No, a single-phase motor cannot be used. Doing so will cause a failure.

The Inverter creates a virtual alternating current with high-speed switching.

If the Inverter is connected to a single-phase capacitor-start induction motor, the capacitor will overheat and burn due to repetitive charging and discharging, so do not connect to this kind of motor.

In addition, if the Inverter is connected to a split-phase-start induction motor or repulsion-start induction motor, the motor's internal centrifugal switch will not operate, and the starting coil may overheat, so do not connect these kinds of motors. Use a three-phase motor.

Inverter with RS-422A / RS-485 Communications

Are there Inverters with RS-422A/485 communications?

Presently, the following models are capable of RS-422A/485 communications.

• 3G3MV Series
• 3G3RV Series
• 3G3JV Series

Note:In the 3G3JV Series, a 3G3JV-PSI485J RS-422/485 Communications Unit (sold separately) is required to support RS-422A/485 communications.

The communications protocol conforms to MODBUS communications protocol, so no other communications protocols can coexist with the MODBUS. Only Inverter-related products can be connected as Slaves.

Refer to the user's manual for details on the actual communications protocol.

Operate and Stop an Inverter using Magnetic Contactor

Can an Inverter be operated and stopped using a magnetic contactor (MC)?

An Inverter can be operated and stopped by using a magnetic contactor (MC) on the primary side, but for the following reasons, do not turn the power supply ON and OFF frequently.

1. If the power supply is turned ON again before the inrush current prevention resistor cools, built-up heat will burn the resistor (abnormal resistor heat).
2. The service life of the relay that short-circuits the inrush current prevention resistor will be shortened.
3. The service life of the capacitor for the power supply section will be shortened.

A limit of once every 30 minutes is recommended for turning the power supply ON and OFF.

One Inverter to Drive Multiple Motors

Can one Inverter be used to drive multiple motors?

Yes. Make the settings under the following condition:

Inverter rated current ≥ Motor rated current × 1.1 (at continuous operation)

Check whether the current is within the Inverter's overload capacity at maximum load. Electronic thermal relays cannot be used, so install a protective thermal relay for each motor.

Calculate Rotational Speed of an Induction Motor

We are using an Inverter for speed control. How can we calculate the rotational speed of an induction motor?

Generally, the speed (N) of an induction motor is expressed by the following formula:

N = (120f/P) × (1 - S) (rpm)

f: Primary frequency

P: Number of motor poles

S: Slip

Example:

Where f = 60 Hz, P = 4 poles, and S = 3%,

N = ( (120 × 60) ⁄ 4) × (1 − 0.03) = 1,746 (rpm)