A. On moving machinery, anchor the leads securely. As little movement as possible should be allowed close to where the leads emerge from the heater. A loop in the lead wire will frequently extend lead life. If application conditions result in continual lead flexing, terminate the cartridge heater leads at a terminal block which moves from the heated assembly. Flexing is transferred to the extension leads which can be economically replaced.
B. For rapidly vibrating equipment, employ the terminal block described above. Keep leads from heater to block short and well supported to prevent lead movement due to vibration.
C. Protect leads from spray, oil, and abrasive. Contaminating liquids and vapors can enter unsealed cartridge heaters and cause insulation breakdown.
D. Avoid tape on leads where they emerge from the cartridge heater. The adhesive on some tapes can enter the heater and turn to carbon which is electrically conductive. Where glass tape cannot be avoided, a tape with a silicone based adhesive is suggested.
E. Design the installation so that the leads are in an ambient temperature which doesn’t exceed the rating on the lead insulation (392°F for standard leads).Where temperatures require it, use nickel or nickel plated copper wire with Teflon, silicone impregnated fiberglass or rockbestos insulation to extend leaders.
F. Graphite and other lubricants to help insert the cartridge heater into the hole are generally not recommended. These are electrically conductive and can get on the lead end of the heater unless extra care is taken.
G. As operating temperatures go up, thermal insulation on the heated part becomes more desirable to conserve heat. Thermal insulation results in lower wattage requirements and therefore lower Watt density on the heaters. Other benefits are more even work temperatures and greater operator safety and comfort.
H. Leads must not extend into the hole containing the cartridge heater. Generally, the lead end of the heater should be flush with surface.
Ing. Carlos Aquino
Sales Technical Support
H. Matamoros, Tamaulipas, México
Tel +52 (868) 813-2271
Fax +52 (868) 813-7319
Nextel: 62*209142*3
dircasa@prodigy.net.mx
