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Product Application
Crohm Series CW wirewound resistors are frequently used for light to medium duty braking of variable frequence drives, speed regulation, wye-delta starting, heating applications, elevator controls, high resistance neutral grounding and any type of AC or DC power circuit. The Series CW resistors are available in resistance values ranging between 0.2 to 300 ohms and corresponding current ranges between 35 and 1 amp.
Product Design
Crohm Series CW wirewound resistors feature a high quality stainless resistor alloy wound into a long spring then wrapped onto a spirally grooved ceramic insulating core. The resistor element is attached at each end of the resistor to a robust stainless steel terminal that is clamped to the core . The open-type design allows the resistor element to come in direct contact with ambient air allowing it to cool more efficiently than enamel coated resistors. The insulating core is produced from cordierite which offers excellent thermal shock resistance and sound mechanical strength. A 3/8" diameter hole runs through the center of the core to except 1/4 to 5/16" diameter threaded rod to offer simple installation and mounting options.
Product Specifications
- Voltage Insulation: 1000 volts
- Insulation Resistance (Dry): 1000 MΩ minimum
- Resistance Tolerance: ± 10% standard, Contact factory for if lower tolerances are required.
- Coeffient of Resistivity: As the element temperature rises the resistance value will increase. Expect an approximate resistance increase of 5% at full operating temperature.
- Operating Temperature: 375°C temperature rise above ambient.
- Ambient Temperature: The power ratings are based on a ambient temperature of 40°C. For higher ambient temperatures decrease power ratings approximately 10% for 50°C, 20% for 80°C and 30% for 100°C.
Product Ordering Information
The part number is specified as follows: CW (resistance x 100). As an example, the part number for a 10 ohm, 384 watt wirewound resistor is CW1000. See the table below for a full list of standard part numbers.
Product Ratings and Dimensions
| Part Number | Resistance (Ohms) | Power (Watts) | Current (Amps) |
| CW20 | 0.20 | 250 | 35 |
| CW25 | 0.25 | 256 | 32 |
| CW30 | 0.30 | 288 | 31 |
| CW35 | 0.35 | 294 | 29 |
| CW40 | 0.40 | 314 | 28 |
| CW50 | 0.50 | 365 | 27 |
| CW70 | 0.70 | 339 | 22 |
| CW100 | 1.0 | 324 | 18 |
| CW150 | 1.5 | 338 | 15 |
| CW200 | 2.0 | 338 | 13 |
| CW250 | 2.5 | 360 | 12 |
| CW300 | 3.0 | 363 | 11 |
| CW350 | 3.5 | 386 | 10.5 |
| CW400 | 4.0 | 400 | 10 |
| CW450 | 4.5 | 381 | 9.2 |
| CW500 | 5.0 | 361 | 8.5 |
| CW550 | 5.5 | 352 | 8.0 |
| CW600 | 6.0 | 347 | 7.6 |
| CW650 | 6.5 | 365 | 7.5 |
| CW700 | 7.0 | 373 | 7.3 |
| CW750 | 7.5 | 388 | 7.2 |
| CW800 | 8.0 | 403 | 7.1 |
| CW850 | 8.5 | 417 | 7.0 |
| CW900 | 9.0 | 404 | 6.7 |
| CW1000 | 10.0 | 384 | 6.2 |
| CW1100 | 11.0 | 396 | 6.0 |
| CW1200 | 12.0 | 404 | 5.8 |
| CW1300 | 13.0 | 407 | 5.6 |
| CW1400 | 14.0 | 408 | 5.4 |
| CW1500 | 15.0 | 421 | 5.3 |
| CW1600 | 16.0 | 416 | 5.1 |
| CW1700 | 17.0 | 408 | 4.9 |
| CW1800 | 18.0 | 398 | 4.7 |
| CW2000 | 20.0 | 423 | 4.6 |
| CW2200 | 22.0 | 388 | 4.2 |
| CW2400 | 24.0 | 384 | 4.0 |
| CW2700 | 27.0 | 350 | 3.6 |
| CW3000 | 30.0 | 347 | 3.4 |
| CW3500 | 35.0 | 358 | 3.2 |
| CW4000 | 40.0 | 360 | 3.0 |
| CW4500 | 45.0 | 281 | 2.5 |
| CW5000 | 50.0 | 264 | 2.3 |
| CW6000 | 60.0 | 264 | 2.1 |
| CW7000 | 70.0 | 280 | 2.0 |
| CW8000 | 80.0 | 259 | 1.8 |
| CW9000 | 90.0 | 260 | 1.7 |
| CW10000 | 100.0 | 256 | 1.6 |
| CW11000 | 110.0 | 247 | 1.5 |
| CW12000 | 120.0 | 252 | 1.45 |
| CW13500 | 135.0 | 246 | 1.35 |
| CW15000 | 150.0 | 254 | 1.3 |
| CW17500 | 175.0 | 252 | 1.2 |
| CW20000 | 200.0 | 242 | 1.1 |
| CW22500 | 225.0 | 248 | 1.05 |
| CW25000 | 250.0 | 250 | 1.0 |
| CW27500 | 275.0 | 250 | 0.95 |
| CW30000 | 300.0 | 243 | 0.90 |
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