E1 Electrical Fundamentals. # 4 - Symbols and Wiring Diagrams

Transcription

1 E1 Electrical Fundamentals # 4 - Symbols and Wiring Diagrams

2 Loads Electrical Loads onsume electricity Do work Examples: Motors Solenoids Heaters Lights 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 2

3 ommon symbols: Motors (Letters tell what motor is represented) OMP EFM IFM OMPressor Evaporator Fan Motor Indoor Fan Motor OMP FM OFM OMP ondenser Fan Motor Outdoor Fan Motor 3

4 Solenoid When current flows through a coil of wire it creates a magnetic field This will cause an action in a relay or valve Electrical symbol for a solenoid coil: 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 4

5 Solenoid Valve Magnetic coil energized Plunger pulled up Power off Plunger drops Plunger Fluid stops Fluid flows Seat 5

6 Heaters onvert electrical energy to heat Symbol for resistance heaters: Examples of heaters: Auxiliary strip heaters rankcase heaters 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 6

7 Signal Lights Used to show when something is operating, or when there is a problem. Symbol for signal lights: RBG Letter in the center denotes bulb color: R Red B Blue G Green, etc. 7

8 ontactor It is a mechanical switch, operated by a magnetic coil Energizing the coil closes the contacts Power flows through the contacts to the load For more on contactors: See Topic E2 Subject 3 ontactors and Motor Starters 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 8

9 ontactor utaway LINE ONTROL IRUIT 1 Power In 2 oil 3 ontacts 4 Power Out LOAD 9

10 Symbols for ontactors oil ontact Single pole Double pole Triple pole 115v v, v, 3 Symbols are shown de-energized (no power) with contacts normally open 10

11 Visualizing symbols with power on The following slide illustrates what happens when the power is turned on 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 11

12 ontactor coil energized ontacts close oil ontact Single pole Double pole Triple pole 115v v, v, 3 12

13 Relays Similar to contactors Usually under 20 amp capacity ontacts may be: Normally open (NO) Normally closed (N) Or a combination of NO and N 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 13

14 Symbols for RELAYS oil de-energized (no power) Normally Open NO Single pole Normally losed N Double pole #1 NO #2 N Triple pole #1 N #2 NO #3 N 14

15 Visualizing symbols with power on The following slide illustrates what happens when the power is turned on 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 15

16 Symbols for RELAYS oil energized (powered up) Normally Open NO Single pole Normally losed N Double pole #1 NO #2 N Triple pole #1 N #2 NO #3 N 16

17 Introduction to switches Switches open and close contacts to control a load ontact: the conducting part of a switch Poles: the number of contacts in a switch Throw: the number of closed contact positions per pole 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 17

18 Single Throw Switch Symbols Switch closed open Single Pole Single Throw (SPST) L1 L2 Switch closed open Double Pole Single Throw (DPST) 18

19 Double Throw Switches Each switch position closes a circuit 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 19

20 Single Pole - Double Throw (DPDT) ontacts 1-2 closed open 2 1 ontacts 1-3 closed open 3 20

21 Double Pole Double Throw (DPDT) ontacts closed ontacts closed 21

22 Thermostats Symbol depicts a bimetal spring which closes and opens the contacts O R B G W Y Tstats are usually shown in their normal position, which is open 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 22

23 Symbols for Thermostats ooling thermostat In actual operation As the temperature goes up the rise in temperature causes the bimetal to expand the expanded bimetal raises the arm the raised arm closes the contacts 23

24 Symbols for Thermostats Heating thermostat In actual operation As the room temperature falls the fall in temperature causes the bimetal to contract the contracted bimetal pulls down on the arm the arm closes the contacts 24

25 Pressure ontrols Symbol depicts a bellows which operates the contacts Pressure safety controls are usually shown in their normal position, which is closed 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 25

26 Low Pressure ontrol 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 26

27 Symbols for Pressure ontrols Low pressure control In actual operation As the system pressure falls the fall in pressure causes the bellows to deflate the deflated bellows pulls down on the arm the arm opens the contacts 27

28 Symbols for Pressure ontrols High pressure control In actual operation As the system pressure rises the rise in pressure causes the bellows to inflate the inflated bellows raises the arm the raised arm opens the contacts 28

29 Fuses and Overloads Symbols for safety devices, such as fuses and overloads, are usually shown closed 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 29

30 Safety Device Symbols Bimetal overload: High heat and high amperage open this overload switch. Thermal overload relay: Excessive amperage heats the thermal element, which opens the switch. Magnetic overload relay: Excessive amperage creates a magnetic field, which opens the switch. 30

31 Introduction to Wiring Diagrams The following slide is a diagram of an attic exhaust fan The fan is controlled by a standard switch 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 31

32 Attic Exhaust Fan L1 N Switch controls fan FM 32

33 Adding controls to the diagram A thermostat replaces the standard switch This allows the fan to operate automatically, based on attic temperatures 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 33

34 Simple ircuit for Attic Exhaust Fan L1 N Add a Thermostat FM 34

35 Schematic Diagrams The wiring diagram on the following slide is a very basic air conditioning unit: The diagram animations show how energizing a relay coil will close a set of contacts 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 35

36 A/ Unit with Line Voltage ontrols L1 OMP ompressor runs L2 LEGEND OMP: ompressor BM Blower runs BM: Blower motor BR : ontactor coil ontactor switch TS Heat closes Tstat BR TS: Thermostat BR: Blower relay Blower relay switch 36

37 Schematic Diagrams The diagram on the following slide is a little more complex A transformer is used to supply power to a low voltage control circuit 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 37

38 Air onditioner Schematic Diagram L1 IFR R R (Low voltage controls) On Auto OMP FM IFM HPS LPS IT T Y G TRANS IFR R 38 L2 LEGEND OMP: ompressor FM: ondenser fan motor IFM: Indoor fan motor : ontactor IFR: Indoor fan relay R: ontrol relay HPS: High pressure switch LPS: Low pressure switch IT: omp. Internal tstat Trans: Transformer R: Red tstat terminal T: ooling Thermostat Y: Yellow tstat terminal G: Green tstat terminal

39 Schematic Diagrams The next slide shows how the low voltage side relates to the high voltage side of the system 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 39

40 Air onditioner Schematic Diagram L1 IFR R R (Low voltage controls) On Auto Y OMP FM IFM HPS LPS IT T G TRANS IFR R 40 L2 LEGEND : ontactor FM: ondenser fan motor IT: omp. Internal tstat OMP: ompressor R: ontrol relay T: ooling Thermostat HPS: High pressure switch LPS: Low pressure switch IFM: Indoor fan motor IFR: Indoor fan relay Trans: Transformer G: Green tstat terminal R: Red tstat terminal Y: Yellow tstat terminal heck out fan circuit Turn Fan ON

41 HVAR Industry Standards for Electrical Diagrams How switch contacts are shown on wiring diagrams: Operating controls are shown in the open position Example: Thermostats and fan switches Safety controls are shown in the normal position Example: High pressure control (closed) Example: High limit switch (closed) Relay contacts are shown with coil de-energized Example: Indoor Fan Relay NO contacts (open) Example: Indoor Fan relay N contacts (closed) 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 41

42 L1 Schematic Diagram of A/ Unit with Gas Heating R IFR ool Off Heat omp On Auto Y FM T W HT FS Low High TRANS G LS IFM IFR R GV L2 Operating controls shown in the open position Fan switch (FS) ooling Tstat (T) Heating Tstat (HT) Relay switches shown with coil de-energized. Indoor Fan Relay (IFR) coil Normally open contacts Normally closed contacts Safety controls shown in the normal position Limit Switch (LS) 42

43 HVAR Industry Standards for Electrical Diagrams Detailed Schematic Numbers on the left are line or circuit numbers Numbers on the right indicate switching information: Which sets of contacts the relay controls (line number) ontact configuration (NO or N) 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 43

44 Detailed Schematic Diagram L1 L2 1 omp Each line is numbered 2 IFR FM Each line has a load R ool Off Heat On Auto Y T W HT FS Low High TRANS G LS IFM IFR R GV (3, 4) (1) Location of relay s switch contacts Underlined numbers are normally closed (N) contacts 44

45 Reading wiring diagrams Try to visualize what happens when the controls close and power energizes loads The following slide illustrates continuous fan operation 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 45

46 L1 ontinuous Fan Operation L2 1 omp 2 3 IFR FM High 4 - Fan motor will now run continuously on high speed in Off, Heat, or A/ settings R ool Off Heat On Auto Y T W HT FS Low TRANS G LS IFM IFR R GV (3,4) (1) 3 - Fan relay contacts change position 1 - Switch fan to On 2 - Fan relay coil energized 46

47 Reading wiring diagrams Which controls, switches, and loads are affected when the A/ is turned on? 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 47

48 1 L1 ooling Mode Auto Fan omp L2 7 - ontactor closes (ompressor and ondenser Fan start) R IFR ool Off Heat On Auto Y W HT FM T FS Low High TRANS G LS IFM IFR R GV (3,4) (1) 4 - Fan Relay contacts change position 5 - Fan motor starts (higher fan speeds are used in A/) 6 - A/ contactor coil energized 3 - Fan relay coil energized 2 - Room temperature rises 1 - Switch t-stat to cool 48

49 Reading wiring diagrams Which controls, switches, and loads are affected when the Heat is turned on? 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 49

50 1 L1 Heating Mode Auto Fan omp L2 Note: Few controls are needed for heating 2 3 IFR FM High 5 - Fan motor starts on low speed R ool Off Heat On Auto Y T W HT FS Low TRANS G LS IFM IFR R GV (3,4) (1) 4 - Furnace heat rises, fan switch closes 3 - Gas valve opens 2 - Room temperature falls 1 - Switch t-stat to heat 50

51 Four Schematics Show Operation The diagrams on the following slides show these conditions: 1. Evaporator motor operation 2. ondenser motor operation 3. ompressor operation 4. rankcase heater operation 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 51

52 FIELD L2 POWER L1 SUPPLY L3 Neutral Equip end 1 SW OFF FAN L1 1 2 A v 24v LB LA IF TRAN Start Indoor Fan Motor (IFM) HR H OMP IFM FR 1 IF 2 SHEMATI 1 3 Indoor fan motor STARTS REMOTE FM OUTDOOR FAN MOTOR SEPARATE POWER SOURE L4 L5 OOL 2 TB1 HR 1 T 3 Switch fan on LO LPS LO LOGI 52 HPS IFM contactor energized 1 FR HR LO OFR HR IF TRAN LO IF

53 FIELD POWER SUPPLY Neutral L2 L1 L Start ondenser Fan Motor (FM) LB LA IF SHEMATI OMP IFM 2 FM Starts Equip end 1 SW OFF FAN L1 1 2 A 240v 24v 11 TRAN 21 4 HR 5 2 H FR IF 2 REMOTE FM OUTDOOR FAN MOTOR 2 2 SEPARATE POWER SOURE L4 L5 1 T OOL 2 3 TB1 4 FR 1 HR LO 5 2 LO LOGI 1 OFR HR Switch to OOL 3 LO LPS HPS IF TRAN Tstat loses FM relay energized 1 LO HR 2 IF 53

54 FIELD POWER SUPPLY Neutral L2 L1 L IF Start ompressor (omp) LB LA SHEMATI OMP IFM ompressor Starts 3 Equip end 1 SW OFF FAN L1 1 2 A 240v 24v 11 TRAN 21 HR H FR IF 2 REMOTE FM OUTDOOR FAN MOTOR 2 2 SEPARATE POWER SOURE L4 L5 OOL 2 TB1 HR 1 T 3 4 FR 1 LO 5 2 LO LOGI 1 OFR HR 3 LO LPS HPS IF TRAN 1 LO OMP contactor energized HR 2 IF 54

55 FIELD POWER SUPPLY Neutral L2 L1 L Shut off rankcase Heater (HR) LB SHEMATI LA OMP 1 IF IFM 4 H Off Equip end 1 SW OFF FAN L1 1 2 A v TRAN 24v HR 2 H FR IF 2 REMOTE FM 2 2 L4 L5 OOL 2 TB1 HR 1 T 3 4 FR 1 LO 5 2 LO LOGI 1 OFR HR 3 LO LPS HPS IF TRAN 1 LO HR relay energized HR 2 IF 55

56 Large Air onditioning System Diagram Part winding compressors require two contactors 1 st contactor pulls in, then 2 nd contactor pulls in 1-3 seconds later ompressor starts easier, less wear Outdoor thermostats control 2 nd and 3 rd condenser fans 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 56

57 L1 L2 L3 B1 B2 B3 FU ommercial A/ remote condensing unit 1 2 OMP OF1 OF2 OF3 OFM1 OFM2 OFM3 : ontactor B: ircuit breaker H: rankcase heater R: ontrol Relay DLT: Discharge line tstat FU: Fuse HPS: High pressure switch LPS: Low pressure switch OF: Outdoor fan contactor OFM: Outdoor fan motor OL: Overload OPS: Oil pressure switch OTS: Outdoor temperature switch TDR: Time delay relay 1 st Winding energized 2 nd Winding energized, ompressor starts R R R LPS HPS DLT From building control system R OPS OL1 OL2 TS1 H TDR OF1 OF2 OF3 1 TDR 2 rankcase heater off ompressor contactor #1 on Time delay relay starts Time delay contacts close ompressor contactor #2 on One Outdoor fan starts Other Outdoor fans start all for cooling TS2 57

58 2005 Refrigeration Training Services - E1#4 Symbols and Wiring Diagrams v1.1 58