Abbreviations are frequently used in control circuits. The following list identifies a few commonly used abbreviations: –
| MTR | Motor |
| MN | Manual |
| NEG | Negative |
| NEUT | Neutral |
| NC | Normally Closed |
| NO | Normally Open |
| OHM | Ohmmeter |
| OL | Overload |
| PB | Pushbutton |
| PH | Phase |
| POS | Positive |
| PRI | Primary |
| PS | Pressure Switch |
| R | Reverse |
| REC | Rectifier |
| RES | Resistor |
| RH | Rheostat |
| S | Switch |
| SEC | Secondary |
| SOL | Solenoid |
| SP | Single-Pole |
| SPDT | Single-Pole, DoubleThrow |
| SPST | Single-Pole, SingleThrow |
| SS | Selector Switch |
| SSW | Safety Switch |
| T | Transformer |
| TB | Terminal Board |
| TD | Time Delay |
| THS | Thermostat Switch |
| TR | Time Delay Relay |
| U | Up |
| UV | UnderVoltage |
| VFD | Variable Frequency Drive |
| XFR | Transformer |
| AC | Alternating Current |
| ALM | Alarm |
| AM | Ammeter |
| ARM | Armature |
| AU | Automatic |
| BAT | Battery |
| BR | Brake Relay |
| CAP | Capacitor |
| CB | Circuit Breaker |
| CKT | Circuit |
| CONT | Control |
| CR | Control Relay |
| CT | CurrentTransformer |
| D | Down |
| DC | Direct Current |
| DISC | Disconnect Switch |
| DP | Double-Pole |
| DPDT | Double-Pole, Double-Throw |
| DPST | Double-Pole, Single-Throw |
| DT | DoubleThrow |
| F | Forward |
| FREQ | Frequency |
| FTS | Foot Switch |
| FU | Fuse |
| GEN | Generator |
| GRD | Ground |
| HOA | Hand/Off/Auto Selector Switch |
| IC | Integrated Circuit |
| INTLK | Interlock |
| IOL | Instanstaneous Overload |
| JB | Junction Box |
| LS | Limit Switch |
| LT | Lamp |
| M | Motor Starter |
AUTHORS
1.Bunty B. Bommera
2.Dakshata U. Kamble