Contact Rail
Heating
Comparison of
RTR’s Constant Wattage, Power-Limiting & Self-Regulating Heater
Technologies
Power Limiting Technology was
developed from, and is very similar to, Constant Wattage Technology.
Both are parallel zone heater constructions. The heating element in
a Constant Wattage Zone Cable is a single strand of fine gauge
nichrome wire wrapped around the buss conductors, making contact at the
notched nodes, which alternate at intervals down the two buss wires.
The heating element in a
Power Limiting Cable is a composite of a fine gauge element wire, of a
different alloy, which is spun around a fiberglass thread. This composite
is then wrapped around the buss conductors, making contact at the nodes,
in the same fashion as the constant wattage cable. The result of
the spun composite heating element is increased strength and a more robust
cable construction.
The result of the different alloy used
in Power Limiting Technology is a slight positive temperature
coefficient (PTC) effect in the metallic heating element. The
Self-Regulating Index (the slope of power output vs. temperature) of the
constant wattage nichrome element is virtually 0.00. Therefore the power
output of a Constant Wattage Cable is constant at any ambient or
substrate temperature.
The Self-Regulating Index
of the Power Limiting Element is in the 0.01 to 0.02 range.
Therefore, the power output of a Power Limiting Cable will reduce
slightly with increasing ambient or substrate temperature.
To put this level of PTC behavior in
perspective, however, true Self-Regulating Cables have Self-Regulating
Indexes in the 0.06 to 0.15 range, roughly 5 times the slope of power
limiting cables. Therefore, Self-Regulating Cables reduce power
output much more than Power Limiting Cables. Power
Limiting Cables behave much more like
Constant Wattage Cables than Self-Regulating Cables and are, in
fact, considered a spin-off variety of Constant Wattage Cable with
the advantage of a stronger heating element.
RTR Self-Regulating Technology
How it Works!
RTR Heaters
automatically adjust their power output to compensate for temperature
changes. Heat is generated as electric current passes through the
self-regulating core between the buss wires. As the temperature drops, the
number of electrical paths through the core increases and more heat is
produced. Conversely, as the temperature rises, the core has fewer
electrical paths, less heat is produced and electrical draw is reduced.
This Self-Regulation occurs along the
full length of the heater circuit. The parallel circuit design allows the
heater to raise or lower its power output relative to different ambient
temperatures sensed along the length of the heater circuit.
Contact Rail Heater Systems Reference List
|
Description |
Customer |
Qty |
Program/Location |
|
Guideway
Htr |
OATS |
166,456 |
O'Hare Airport |
|
Guideway
Htr |
Tracer |
6,800 |
Beijing Airport |
|
Self Regulating Contact
Rail Heater and Accessories |
Alumuninum
Alouette |
300 |
Rail Maintenance |
|
Self Regulating Contact
Rail Heater and Accessories |
Blumenthal
Kahn |
23,738 |
MDMTA
- NE Yard |
|
Self Regulating Contact
Rail Heater and Accessories |
Crane Pro |
200 |
Crane Rail Heating |
|
Self Regulating Contact
Rail Heater and Accessories |
CTA |
43,500 |
MRO
Stock |
|
Self Regulating Contact
Rail Heater and Accessories |
Cushman&
Wakefield |
400 |
Crane Rail Heating |
|
Self Regulating Contact
Rail Heater and Accessories |
Detroit Trans |
410 |
Power Rail De-Icing |
|
Self Regulating Contact
Rail Heater and Accessories |
Eng Equip |
60 |
Running Rail De-Icing |
|
Self Regulating Contact
Rail Heater and Accessories |
PATH |
41,093 |
Harrison Yard & Main Line |
|
Self Regulating Contact
Rail Heater and Accessories |
Southern Av |
300 |
Antenna De-Icing |
|
Self Regulating Contact
Rail Heater and Accessories |
Tracer |
32,234 |
Detroit |
|
Self Regulating Contact
Rail Heater and Accessories |
Truland |
13,734 |
New Carrolton, Shady Grove, NY Ave |
|
Self Regulating Contact
Rail Heater and Accessories |
TTC |
32,200 |
Scarboro
Line |
|
Self Regulating Contact
Rail Heater and Accessories |
Tyco |
34,465 |
CTA
Blue Line |
|
Self Regulating Contact
Rail Heater and Accessories |
Tyco |
4,440 |
CTA
Red Line |
|
Self Regulating Contact
Rail Heater and Accessories |
WESCO |
200 |
Crane Rail Heating |
|
Self Regulating Contact
Rail Heater and Accessories |
WMATA |
10,000 |
WMATA |
|
PTCZ
Contact Rail
Heater and Accessories |
MBTA |
5,250 |
Cabot Yard |
|
PTCZ
Contact Rail
Heater and Accessories |
NYCT |
750 |
Traction Power Maintenance |
|
PTCZ
Contact Rail
Heater and Accessories |
PATCO |
3,000 |
Traction Power Maintenance |
|
PTCZ
Contact Rail
Heater and Accessories |
SEPTA |
4,413 |
Norris Town High Speed |
|
PTCZ
Contact Rail
Heater and Accessories |
WMATA |
350,000 |
WMATA |
|
Contact Rail Heater Controls |
Aluminium
Alouette |
1 |
Rail Maintenance |
|
Contact Rail Heater Controls |
Truland |
178 |
WMATA
- New Carrolton, Shady Grove, NY Ave |
|
Contact Rail Heater Controls |
Blumenthal
Kahn |
53 |
MDMTA
- NE Yard |
|
Contact Rail Heater
Junction & Fuse Box |
Blumenthal
Kahn |
222 |
MDMTA
- NE Yard |
|
Contact Rail Heater
Junction & Fuse Box |
Truland |
26 |
WMATA
- New Carrolton, Shady Grove, NY Ave |
|
RF
CRH Controls |
PATH |
36 |
Harrison Yard & Main Line |
