When troubleshooting a motor controller, all...

When troubleshooting a motor controller, all...

Question 1 of 270705eccefa4bacbc34ba4d48515

When troubleshooting a motor controller, all indications are that a relay coil should be energized. If there was no magnetic pull, with rated voltage measured across the coil, what would be the most probable cause?

Question 1 of 27070

Q

When troubleshooting a motor controller, all indications are that a relay coil should be energized. If there was no magnetic pull, with rated voltage measured across the coil, what would be the most probable cause?

🔍 Key Concepts

• Relay coil operation when rated voltage is applied • What an open coil vs. a stuck armature would look like when measuring voltage • How series control components (fuses, auxiliary contacts) affect voltage readings at the coil

💭 Think About

• If you truly measure rated voltage across the coil terminals, what does that tell you about everything connected in series with the coil? • Would a stuck armature prevent magnetic pull even if the coil is good and has voltage? Think about what physically creates magnetic pull. • In which fault condition would you still see full rated voltage at the coil, but no current flowing and therefore no magnetism?

✅ Before You Answer

• Verify where the voltage is being measured: directly across the coil terminals, not just in the control circuit. • Confirm that if a fuse or series contact were open, would you still be able to read rated voltage directly across the coil? • Consider which fault would allow voltage to appear at the coil but block current flow through the coil windings, eliminating magnetic pull.