Electrical Controls weeks 1-6

The requirements in Section 16 are based on two assumptions:

1. Voltages not more than 30V (I.e. Extra-low voltages) do Not constitute a Shock Hazard

2. Power not more than 100V•A do Not constitute a Fire Hazrad

Class 1 Transformers:

1. Typically not class labeled

2. >100V•A

3. Can have any secondary voltage

4. Must have current limiting secondary (fuse or circuit breaker)

Class 2 Transformers:

1. Must be labeled class 2

2. <100V•A

3. Maximum secondary voltage of 30V

4. Current is limited by resistance of the secondary coil

Class 1 circuit:

1. Ranges from 100V•A - 1000V•A

2. Must be fused

Class 2 circuits:

1. No fuse or breaker necessary if supplied with class 2 transformer

2. Fuse or breaker required if supplied with class 1 transformer to limit circuit to 100V•A

3. Max voltage of 150

Voltage, Current, and Power restrictions for Class 1:

CEC 16-100

Voltage, Current, and Power restrictions for Class 2:

CEC 16-200

Series Circuits:

1. Current is the same through all devices

2. One path for Voltage & Current

3. Input and output devices can be wired in series

4. Output devices should avoid being wired in series

Parallel Circuits:

1. Different Current flow through all devices

2. Multiple path pathways for Voltage and Current

3. Input and output devices can both be wired in parallel

What kind of circuit is this?

Series

What kind of circuit is this?

Parallel

What is a Relay?

An electromechanical switch that contains auxiliary contacts

Current ratings for most relays…

Can vary from 1 - 10 amperes

Once Relays are added to a circuit it becomes:

Remote control

What are the different types of Relays?

1. 8 or 11 pin

2. Normally open or Normally closed

What are COMS on a 8 pin relay?

2 & 7 (coil) 1, 8

What are COMS on a 11 pin relay?

2 & 10 (coil) 1, 6, 11