Digital 3 Phase Voltmeter Connection Diagram For 440 Volts Testing

In three phase power system, we wire and install the voltmeter to measure the AC voltage, in this post you will learn about the 3 phase voltmeter connection diagram for a digital voltmeter. I already published posts about the three phase volt meter wiring / installation. Also the volt meter selector switch wiring diagram / installation for 3 phase and also for three phase 4 wire system. In his post I am going to write about the three phase digital voltmeter wiring for single phase and 3 phase, but I only share the diagram about the 3 phase digital panel voltmeter, in which I use it for line to line voltage measurement.

3 Phase Voltmeter Connection Diagram For Line To Line Voltage Testing (440V)

In a 3 phase analog voltage meter we have 2 terminals or contacts to provide the supply. We can connect our single phase (neutral and Phase) to these connects or connection point to measure the voltage between neutral and phase. But as you know that meter is design for three phase system (0 to 500 volts) so always use it for measurement voltage between line to line (phase to phase).

So we connect two lines (i.e. L1 and L2) to analog voltage meter to measure the voltage between Line 1 to Line 2. But in digital we have some different connection and we also required the neutral or we can said if we are going to install a digital voltmeter to measure voltage between line to line then we also required the neutral to operate digital volt meter.

In digital voltmeter we have two types of input contacts, one for to operate digital V meter or to operate the display of meter. The 2nd input for voltage to measure. Here I had shown a diagram in which I wire the voltmeter for measuring voltage between L1 and L2.

In above digital 3 phase voltmeter connection diagram. I shown the neutral and phase supply goes to 6 and 8 terminals for voltage meter which is for operating the display. As the L1 is connected to the 6 number terminal and this is also line than a wire connection will goes from this point to 2 number terminal.

The 1 and 2 number points are for input AC supply to measure. So we connect the L1 to the 2 number and the L2 wire to 1 terminal.

The above connection for digital voltage meter is for line to line voltage testing. However if you want to wire it for single phase (Neutral to Phase) voltage testing then provide also the single phase 220 supply to the 1 and 2 terminals.

Note the connection diagram can be different for different model of voltmeters. It's depends on company who manufacture the voltmeters. So this is just an example of wring connection. It's incoming supply for display and terminals number can be different in different model of voltmeter. So the better option is that to read the provide guide or diagram of voltmeter and which is provided on side or back side of voltmeter. Here is the above voltmeter example.....

In the above image the voltmeter connection method shown. In which High and Low for input AC supply voltage testing. Note this meter can test voltage from 0 to 500v. In the above diagram AC power terminals are 6 , 7, 8 but in meter only 6 and 8 number contacts available which for 220 volts. However if the 110 V option available and your supply is 110v the connect you supply to 0v and 110v contacts.

(Note every voltmeter have their own diagram and their own connection. So this is not important that the connection name and number are same. Or the connection method is same. So always read the digital meter contacts diagram and then wire it)

Also read

How to wire voltmeters for three phase

How to wire voltmeter selector switch for three phase

Voltmeter selector switch installation for there phase 4 wire system

I hope this post help you to understand the 3 phase voltmeter connection diagram or how to wire / install a digital panel type voltage meter for single phase (220 v) or double line voltage testing (440v).

Identifying starting and running winding of single phase induction motor

Mostly in electrical technology students , a question are serve in his minds about the single phase motor that how to identify starting and running winding. Basically when we talk about the single phase motor wiring or installation connection. We always think about the start , run and common wire or terminals. In one phase motor connection we have three wire are coming from the motor winding which are start , run and common. As you know that we have two types of winding in a single phase motor which we known with name of starting and running winding. The running winding also called the main winding while the starting winding is better known with name of "auxiliary winding". The point where these moth winding are connected is called the common point which we know better with name of "common connection of a one phase motor" or "the common terminal of a single phase refrigerator compressor".

How to Identify starting and running winding in a single phase motor

If you open the single phase motor , you will find out that your motor have two types of winding in which one is made from thick wire gauge and one thin . the thick wire gauge winding is main winding and thin wire gauge winding is starting winding. But this Identification can be done when you open the motor but what you will do if don't want the motor and just want to find out starting and running winding from the main connection plate or connection point.
(Basically to identify starting and running winding is just to find out the start , run and common connection.)

In a single phase motor we have three wires which comes from the both stating and running winding. Which we known with the name of common, start and run connection. To find out the common , start and run wires or connection first read the connection plate diagram and notes to find out which one is common, which one is running and starting. In some one phase motor the the common wire come with black color wire, run as red and start as white color. But this is not important that the connection will come with same colors. Mostly  these color are change. So the better and easy option to to find out the run , start and common wire or connection to read the connection plate diagram or chart. And if you did not find any guide about the connection then follow the below step.


Use a Multi meter You can easily identify the common , starting and running connection of a single phase motor. In the single phase 3 wire motor we have a high resistance between the start and run connection or wire. And if you find out that two wires have a high number of resistance showing on multi meter or ohm meter in three wire then it's means that these two wire are start and run connection and the other one is common. However to complete understand , fallow the below step by step guide

• First of all set your multimeter on ohm testing 
• Then check resistance between wire to wire in 3 wires
• If you find out that two wire have greater resistance between one another then it's mean that these are start and run and the 3rd one is common.
• So you identify the common wire , so the next step to find out which one is start and run wire.
• The method is easy, the resistance between common and staring will greater then the Resistance between common and run wire. So the greater resistance between common and other wire will identify that this is start , starting connection or terminal. So you find out that starting connection. So it's clear the other wire is run connection wire.

To identifying starting and running winding' i means that you are searching about the staring and running and common identification in a single phase motor. So if you are searching for this then the above method is for you. And if you want to identify the starting and running winding then the easy method to open the motor internally. And see which winding wire greater in size. For example is you find out two winding and one winding are made from 21 SWG and 2nd winding is made from 26 Then 21 SWG is greater in size which running winding or main winding and 26 SWG winding is staring or auxiliary winding. 

(Note That the above start, run and common identification method you can use for any single phase induction motor, like ceiling fan, single phase submersible water pump motor, for A/C outdoor coiling fan etc.)

Also read
Single phase 3 wire submersible pump box wiring and installation
Single phase motor ON/OFF using Circuit breaker
Single Phase Motor ON/OFF controlling using contactor / stater
How to find out start , run and common in a refrigerator compressor

I hope this post help you find out how to identify staring and running winding or identification the start, run and common terminals or connection is a single phase motor. If the post help you then kindly share this post. And if you have any question then you can use the below comment section for asking you question. I will try my best to gave answer of your comments.

3 Phase Manual Changeover Switch Wiring Diagram For Generator

As you know that we start from the basic steps. In this post I am writing about 3 phase manual changeover switch wiring diagram or three phase manual transfer switch wiring diagram. As you know that I already published a post and diagram about the manual changeover switch wiring diagram (single phase) with complete installation and wiring connection method. In Today post I am here to write and share a diagram about the three phase manual changeover switch wiring diagram and it's installation with incoming supply from the main supply, incoming supply from the 3 phase generator and outgoing supply to the three phase load. Note that this diagram is about the manual handle type change over switch and IN SHA ALLAH soon I will make a diagram about the rotary type change over switch wiring diagram for single phase, three phases and three phase four wire system.

3 Phase Manual Changeover Switch Wiring Diagram For Generator With Complete Installation Guide

The 3 phase manual changeover switch wiring diagram is too simple and easy connection. For better understanding kindly read the below single phase handle type manual transfer switch post.

Also read

How to wire and install the manual transfer switch for single phase

The three phase changeover wiring connection and installation is too simple and easy connection as I shown in the below diagram. In the below diagram I shown the incoming 3 lines supply wires with read red, yellow and blue colors. The neutral I shown with black color but the neutral- is not used in the three phase manual transfer or changeover switch. The main supply is connected to the switch upper input supply terminals. And the generator supply connected to the bottom- input terminals or connection points of transfer switch as I shown in the below diagram. The output supply is goes to load from output connection points or terminals. I have shown load as three phase induction motor. One thing more if we move the switch handle upper side, the main supply will goes to the load. When we move the transfer switch handle to center-, the switch will on OFF mode. And when we required the generator emergency supply for load then we move the changeover handle to bottom- side.

(Note that this type of switch we use in our country, may be the type or shape will be different as I shown in the diagram but the reason- of publishing this post is that to tech you about the basic working principles- of a transfer or three phase manual changeover switch)

I hope after the above 3 phase manual changeover switch wiring diagram, now you will be complete understood. However you can ask you question according this diagram or post then you can use the below commenting system.