Overhead Railcar HVAC Heaters
Indeeco has designed and built both open coil and finned tubular heaters for a wide variety of space heating applications for more than 40 years. Thirty years ago, we developed the first open coil heater designed specifically for use in railcar systems. This design differs from open coils for commercial and industrial applications in the following respects…
High Voltage Terminal Insulators
High voltage terminal insulators have approximately four times the creepage distance between the terminal and ground — two inches over surface in the railcar design versus 0.5 inches in the commercial HVAC heater design. Moreover, these ceramics are glazed giving a margin of safety at this point of maximum potential difference to ground.
Ribbed Coil Support Insulators
Ribbed coil support insulators have approximately six times the creepage distance: the over ceramic surface between the coil and grounded metal is 1.5 inches in the railcar heater design, versus 0.25 inches for commercial HVAC heater designs.
Low Watt Density Coils
Low watt density coils are designed to operate safely without burnout when the voltage swings as much as 20% above nominal. Since the wattage varies with the square of the voltage, a 20% overvoltage results in a 44% over-wattage. All coils are 80% nickel, 20% chromium, the highest grade of resistance wire.
Double-strength "Sandwiched" Design
Coil insulators are sandwiched between two sheet metal plates, spot welded together to hold the insulators in place. In commercial heaters, insulators are staked into a single plate. The railcar design is substantially sturdier, while still allowing the coil insulators to float freely. This prevents insulators from cracking as the heater expands and contracts.
Stainless Steel Construction
Stainless steel construction is available as well as galvanized steel. Stainless is more resistant to corrosion from heat and water carryover; welded joints need not be specially treated for corrosion.
Mounting devices such as weld nuts, captive nuts, T-bolts and Z-bars are available for attachment to the cooling coil and for attaching accessories such as terminal blocks, heat limiters and thermal cutouts.
Heater-control packages include automatic reset thermal cutouts, heat limiters, terminal boards for high and low voltage connections, all engineered and wired by Indeeco.