HVAC 132 Control Transformer TRANSFORMER A DEVICE THAT

  • Slides: 7
Download presentation
HVAC 132 Control Transformer

HVAC 132 Control Transformer

TRANSFORMER • A DEVICE THAT HAS THE ABILITY TO CHANGE THE VOLTAGE & CURRENT

TRANSFORMER • A DEVICE THAT HAS THE ABILITY TO CHANGE THE VOLTAGE & CURRENT WITHOUT CHANGING THE FREQUENCY • AC/HEATING TRANSFORMERS ARE ISOLATION TRANSFORMERS • MADE UP OF A PRIMARY & A SECONDARY

Step-down Transformer L 1 240 volt Primary T 1 Induced voltage 24 v Secondary

Step-down Transformer L 1 240 volt Primary T 1 Induced voltage 24 v Secondary T 2 L 2 Ratio 10 : 1 Voltage 240 : 24

PRINCIPLE OF OPERATION • OPERATES ON THE PRINCIPLE OF MAGNETIC INDUCTION – WHEN CURRENT

PRINCIPLE OF OPERATION • OPERATES ON THE PRINCIPLE OF MAGNETIC INDUCTION – WHEN CURRENT FLOWS THROUGH THE PRIMARY, IT INDUCES A CURRENT FLOW IN THE SECONDARY – THAT NEW CURRENT FLOWS IN THE OPPOSITE DIRECTION – VOLTAGE IN THE SECONDARY IS DETERMINED BY THE PRIMARY VOLTAGE & THE WINDINGS RATIO

PRINCIPLE OF OPERATION • TRANSFORMERS CAN BE STEP-UP OR STEP-DOWN • STEP-DOWN TRANSFORMERS ARE

PRINCIPLE OF OPERATION • TRANSFORMERS CAN BE STEP-UP OR STEP-DOWN • STEP-DOWN TRANSFORMERS ARE COMMON IN MODERN AC/HEATING APPLICATIONS • 120 VAC TO 24 VAC IS A VERY COMMON CONTROL TRANSFORMER – 5: 1 RATIO OF PRIMARY TO SECONDARY WINDINGS – 5: 1 RATIO OF PRIMARY TO SECONDARY VOLTAGES

VOLTAGE & CURRENT RELATIONSHIPS • TRANSFORMERS ARE VERY EFFICIENT DEVICES • OPERATE AT 95%

VOLTAGE & CURRENT RELATIONSHIPS • TRANSFORMERS ARE VERY EFFICIENT DEVICES • OPERATE AT 95% – 98% EFFICIENCY • CONSIDERED TO BE WORKING AT 100%I. E. POWER IN = POWER OUT

TESTING THE TRANSFORMER 1. CHECK FOR VOLTAGE TO IT 2. CHECK FOR VOLTAGE FROM

TESTING THE TRANSFORMER 1. CHECK FOR VOLTAGE TO IT 2. CHECK FOR VOLTAGE FROM IT 3. OHM PRIMARY: 1. OPEN (OL) 2. SHORT (0 OHMS) 3. GROUNDED (ANY OHMS TO GROUND) 4. OHM SECONDARY: 1. OPEN (OL) 2. SHORT (0 OHMS) 3. GROUNDED (ANY OHMS TO GROUND)