Gates 206 CORD SENSOR Preventive Maintenance Tools

The 550C ships with the flat flexible sensor (7420-0205), which allows one-hand use. Gates offers two optional sensors: the cord sensor (7420-0206) for places the flexible sensor cannot reach, and the inductive sensor (7420-0212), which reads a magnetic field instead of sound and is recommended in noisy or windy locations. The inductive sensor needs a small magnet taped to the back of the belt; magnets come with it, and Gates sells replacements as 7420-1212 in sets of 10. Gates also lists 7420-0212 as the inductive sensor for the earlier 507C meter.

Three values: the belt mass constant (grams per meter per mm of width for synchronous belts, from the table in the 550C manual), the belt width in mm (or the number of strands for V-belts, or ribs for Micro-V), and the span length in mm. The meter stores up to 40 sets of these. It reads 10 to 5000 Hz across three filter ranges (low 10 to 50, standard 10 to 1000, high 900 to 5000) and can display tension, frequency or both. Without sensible non-zero constants it shows frequency but not tension.

Gates warrants the meter to operate for two years from the date of manufacture and will repair or replace it, at its discretion, within that period. Sensors are not covered, and damage from misuse or abuse is excluded. Outside the warranty, Gates offers a paid repair service, with an estimate given after the meter is evaluated in-house. Traceable accuracy certification is also available: the meter comes back with a sticker and certificate. Certification is not covered by the warranty. Any return needs prior approval and an RMA number arranged through a Gates distributor; do not ship a meter to Gates without one.

The rating is the maximum deflection force the tester can read, so choose the smallest one that covers the force your drive calls for. Gates lists the 30 lb single-barrel tester (7401-0076) for small V-belt and synchronous drives, including PowerBand and Poly Chain GT Carbon, and the 66 lb double-barrel (7401-0075) and 165 lb five-barrel (7401-0079) testers for multiple V-belt and large synchronous drives. On the multi-barrel testers, add the readings from each barrel to get the total force. The required deflection force for a Poly Chain drive comes from Formulas 15 and 16 in the Gates drive design manual, or from Gates drive design software.

Both are the same two-piece system: a laser transmitter and a reflector that attach magnetically to the face of a sheave or sprocket and show angular, parallel and third-plane misalignment, with one person operating. The red version is Gates 7420-1000 and measures spans of up to 6 feet or better. The green version, 7420-3000, is about 10 times brighter, which makes it easier to see in high ambient light and over longer distances, up to 15 feet.