Electrical Engineering Guides
-
What Is Transformer Rating Based On?
A transformer’s kVA or MVA rating is an apparent-power capability under declared voltage, frequency, cooling and temperature conditions. It is not a measured kW output and it is…
-
Wye Transformer Calculations: Line, Phase and Winding Quantities
For a balanced wye-connected transformer winding, line current equals winding current, while line-to-line voltage equals sqrt(3) times winding voltage. In this article, winding voltage means the line-to-neutral voltage…
-
Switchyard and HV Area Safety: Access and Work-Zone Checks
Permission to enter a switchyard does not authorize a person to approach exposed high-voltage parts, operate equipment or begin maintenance. A usable access brief connects the named task…
-
Main Bonding Jumper: Purpose, Location and Sizing Checks
The main bonding jumper connects the grounded service conductor to the required protective bonding arrangement at the service. To check its size, first establish that service location, then…
-
GIS Bay Maintenance: Isolation Boundaries and Restoration Checks
A gas-insulated switchgear (GIS) bay outage needs three reconciled boundaries: the primary electrical circuit, the protection/control interfaces and the gas compartments affected by the task. A bay name…
-
Delta Transformer Calculations: Line, Phase and Winding Quantities
For a balanced, sinusoidal delta-connected transformer winding, line-to-line voltage equals winding voltage, while line current equals √3 times winding current. Apply the turns ratio to corresponding winding voltages,…
-
AFCI Breaker Installation: Compatibility, Neutral Routing and Verification
An AFCI breaker installation should be accepted only after the breaker is verified for the actual panel and circuit, its neutral arrangement follows the exact device instructions, and…
-
How to Read a Terminal Block Derating Curve Without Misapplying the Rating
Read a terminal-block derating curve by matching the exact component and test arrangement, locating its defined ambient temperature, and reading the permitted current on the applicable trace. Do…
-
SCADA Specification Checklist: Point Lists, Control Authority and Failure Tests
Specify a supervisory control and data acquisition (SCADA) system through observable operating behavior, not a screen count or a list of protocol names. Each important point, command and…
-
Replacement Three-Phase Induction Motors: Fit, Speed and Duty Checks
Select a replacement three-phase squirrel-cage induction motor by checking the retained machine’s interfaces, not just matching its kilowatt rating. Mechanical fit, operating speed, starting behavior, cooling and control…