Motor control circuits

Symbols used in engine control circuits (Figure 162)

Start press button Stop switch Normally wide open contact Normally closed contact [pic] [pic] [pic] [pic]

Overload Contactor coil Change coil Forward coil [pic] [pic] [pic] [pic]

Termes conseilles


Fig 162

Wiring diagram of any motor control circuit (Figure 163) with power signal (Figure 164) [pic] [pic]

Fig 163 Control routine Fig 164 Power signal

Control circuit and power circuit (Figure 165)


Fig 165

Stop key

The stop key is usually linked in series with the control circuit. This way, when the prevent button can be pressed, it cut off the existing flow from the entire control circuit creating a break in the circuit. The stop switch is a normally closed contact. When it is hard pressed a planting season usually returns it to its normally closed placement.

Start switch

The start button is generally connected in parallel and it is used to provide a momentary current flow through the control routine in order for starting to occur. A start button is a normally open speak to. It usually uses a springtime to return that to its normally wide open position after it has been hard pressed.

Normally open up contact

This is a speak to that is normally open. It only closes whenever the coil is turned on.

Normally closes contact

This can be a speak to that is closed in its normal position. This only starts whenever the coil is usually activated.


This can be a safety device which is used to protect the motor brake lines whenever the motor begins to draw abnormal current. The overload is normally in the form of a relay or perhaps heaters. The heaters will lose or the relay will trip, breaking the outlet and preventing the circulation of current.


Normally, this is used to wide open the normally closed circuits and close the normally open circuits whenever a current passes through it and it is magnetized.

Invert and ahead coil

Both of these coils are being used in an layout so that they will allow the motor unit to run in the forward or perhaps reverse path.


The timer is actually a device which is used to turn on a circuit in a particular period.

Power outlet

This is the element of a outlet the offers power to the motor from the main circuit.

Control signal

This is the part of the circuit that controls the strength circuit. The control circuit and electrical power circuit has to work together.

Pattern control circuit

This can be a type of circuit that will allow only 1 motor to be started at any time. This is carried out because during starting a motor might use up to 5 times the current necessary to run this under normal condition. This more than one motor unit should start 1 time it could cause the breaker to trip frequently and eventually damage this. This is why pattern control is very important. Figure 166 represents a sequence control routine.


Fig. 166 Series control outlet

Operation in the sequence control circuit

Current from L1 goes by through the quit, because it is a normally shut push button, and flow to the first start button. That cannot pass through the start since it is a normally open press button. Plus it cannot move through any of the M1 because they are normally open associates. When the begin button is pressed, current can now movement through the start to M1 (in the circle) through the normally closed get in touch with (usually an overload) also to L2. Seeing that M1 (in the circle) is a coils, it will energize and close both normally open M1. When the start off button is definitely released, it is going to return to the normally open position, however the current can still circulation through M1 (in the circle) to L2 since the normally wide open M1 nonetheless remain sealed. Therefore current will stream...


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