Contactors & Starters
Unlike motor starters, magnetic contactors alone do not provide this critical protection.
What is overload protection?
These relays are electronic switching devices that contain no moving parts.
What are solid-state relays?
While overload relays protect against prolonged overloads, these are best suited to protect against short circuits.
What are fuses?
Transformers used in these control systems typically supply this specific AC voltage.
What is 24V AC?
This term means to close a set of open electrical contacts.
What is make?
These lamps have inrush currents approximately 15 to 17 times greater than their normal operating currents.
What are filament-type lamps?
This specific relay is controlled by a magnetic field.
What is a reed relay?
This type of thermal overload relay reacts to a rise in temperature and requires a cooling-off period before it can be reset.
What is a melting alloy relay?
This device allows lighting relays to be controlled in groups while still allowing individual switch control.
What is a master sequencer?
These contacts are open when the enclosing relay or contactor is de-energized.
What are normally open (NO) contacts?
This component of a contactor acts as an electromagnet when energized to pull the armature and close the circuit.
What is the coil?
These relays are typically used in applications where the hum from electrically held contacts would be disruptive, such as hospitals.
What are mechanically held relays (or contactors)?
These overload relays react only to excessive current rather than heat.
What are magnetic overload relays?
Low-voltage control systems are safer for users and reduce the need for costly runs of these.
What are larger conductors?
This shorted turn of wire in an AC electromagnet prevents chattering contacts and reduces audible hum.
What is a shading coil?
A manual reversing starter uses this type of interlock to ensure both sets of contacts cannot close simultaneously.
What is a mechanical interlock?
This type of timing relay delays contact movement after the relay coil is energized.
What is an on delay?
These overload relays can be field-adjusted and may sometimes be set to reset automatically.
What are bimetallic overload relays?
Whenever possible, low-voltage wiring should be kept apart from this type of wiring.
What is high-voltage (or line-voltage) wiring?
The solenoid coil of a relay is typically designed to work properly within this percentage range of its rated voltage.
What is 80% to 110%?
Due to extreme inrush current, this is the maximum tungsten or infrared load current for a NEMA Size 0 magnetic contactor.
What is 10A?
To control multiple loads using a single-pole push-button, this type of relay is required.
What is a multiple-pole relay?
When selecting thermal overload relays, this factor regarding the local air temperature must be considered.
What is ambient temperature?
Control panels should generally be mounted at this height between two studs.
What is eye level?
Energizing this coil in a latching relay causes it to assume its unlatched position.
What is an unlatch coil?