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Select 270 Type fixed resistors for applications requiring wattage ratings from 12 to 1000 watts.
The 270 Type resistors are equipped with lug terminals suitable for soldering or sturdy bolt connection. When secure mounting is required, the hollow core of these resistors permit fastening with spring-type brackets, thru bolts or thru bolts with slotted-steel brackets.
Suitable for rugged applications, the 270 Type resistors feature all-welded construction and durable lead free vitreous enamel coating.
Mounting brackets not included with resistors (more mounting info).
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FEATURES
- Terminals suitable for soldering or bolt connection
- High wattage applications
- Rugged lead free vitreous enamel coating
- Flame resistant coating
- All-welded construction
- "Fast on" option – see terminal 538
SPECIFICATIONS
Material
- Coating: Lead free vitreous enamel.
- Core: Tubular ceramic.
- Terminals: Solder coated radial lug. RoHS solder composition is 96% Sn, 3.5% Ag, 0.5% Cu
- Derating: Linearly from 100% @ +25°C to 0% @ +350°C.
Electrical
- Tolerance: ±5% 1 ohm and over (J); ±10% under 1 ohm.(K)
- Power rating: Based on 25°C free air rating.
- Overload: 10 times rated wattage for 5 seconds.
- Temperature coefficient: 1 to 20 ohms: ±400 ppm/°C. Above 20 ohms: ±260 ppm/°C
- Dielectric withstanding voltage: 1000 VAC: 12 to 100 watt rating. 3000 VAC: 175 to 225 watt rating (Measured from terminal to mounting bracket)
- To calculate max. amps: use the formula
Power limitations for high resistance values: When resistance exceeds the resistance values listed at right, derate the Power Rating by 25% to improve reliability:
| Power rating | Resistance value |
| 12W | 3,900 ohms |
| 25W | 12,000 ohms |
| 50W | 35,000 ohms |
| 100W | 75,000 ohms |
No power derating necessary for ratings higher than 100 watts.
Mounting hardware info
Core and Terminal Selection for Made to Order Tubular Resistors
Through-Bolt "Dead" Mounting Brackets (PDF)
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