LB
Resistive load bank
A bank of switched resistive elements used to apply a controllable test load to generators, UPS or battery systems.
SLD
Symbols · LB RL
Resistive-reactive load bank
A test load bank combining resistive and inductive steps to load a generator at its rated power factor.
In plain English
What does Resistive-reactive load bank mean?
A resistive-reactive load bank adds inductive reactor steps to resistive elements so that a generator can be tested at its full rated kVA and rated power factor, typically 0.8 lagging. This exercises the alternator excitation, voltage regulator and transformer heating in a way a resistive bank cannot.
A simple example
Drawings show resistor and reactor groups in parallel, each with step switching, connected through a breaker. The power factor range and the kW and kvar totals are written beside the symbol.
What the drawings help you do
Reactive load banks are heavier and more costly, so they are mainly used for commissioning large sets and paralleling tests. The symbol does not show the switching sequence or the instrumentation used to record test results.
This particular reference
A test load bank combining resistive and inductive steps to load a generator at its rated power factor. A resistive-reactive bank tests at rated kVA and power factor; a resistive bank tests at unity power factor only.
- Winding
- A coil of conductor inside an electrical machine or transformer.
- Rating
- A value stating the conditions for which equipment is specified.
- Schematic
- A drawing showing function and connections rather than physical appearance.
Read the source: T-030 liquid-cooled generator set application manual · AutoCAD Electrical: Reactors and inductors
SLD · LB RL
What it represents
A resistive-reactive load bank adds inductive reactor steps to resistive elements so that a generator can be tested at its full rated kVA and rated power factor, typically 0.8 lagging. This exercises the alternator excitation, voltage regulator and transformer heating in a way a resistive bank cannot.
Drawings show resistor and reactor groups in parallel, each with step switching, connected through a breaker. The power factor range and the kW and kvar totals are written beside the symbol.
Reactive load banks are heavier and more costly, so they are mainly used for commissioning large sets and paralleling tests. The symbol does not show the switching sequence or the instrumentation used to record test results.
How to read it
- Read both kW and kvar ratings.
- Check that power factor range matches the generator rating.
Information to show or reference
- State kW, kvar and power factor range.
- Show resistor and reactor steps.
- Reference test procedure.
A distinction that matters
A resistive-reactive bank tests at rated kVA and power factor; a resistive bank tests at unity power factor only.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
T-030 liquid-cooled generator set application manual
Public generator application context for testing.
AutoCAD Electrical: Reactors and inductors
Public reactor symbol family context.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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