The main products

Spare parts spare parts, the DCS control system of PLC system and the robot system spare parts,

Brand advantage: Allen Bradley, BentlyNevada, ABB, Emerson Ovation, Honeywell DCS, Rockwell ICS Triplex, FOXBORO, Schneider PLC, GE Fanuc, Motorola, HIMA, TRICONEX, Prosoft etc. Various kinds of imported industrial parts

Products are widely used in metallurgy, petroleum, glass, aluminum manufacturing, petrochemical industry, coal mine, papermaking, printing, textile printing and dyeing, machinery, electronics, automobile manufacturing, tobacco, plastics machinery, electric power, water conservancy, water treatment/environmental protection, municipal engineering, boiler heating, energy, power transmission and distribution and so on.

SR750-P5-G5-S5-HI-A20-R-T Relay shell

A speed set point value cannot be directly entered (with the ENTER key) within the programmed critical speed band settings. In the event this is attempted, an error message will appear on the 505 front panel display. If another controlling parameter, besides the Speed PID, drives the turbine’s speed into a critical band for longer than five seconds, the speed set point will instantly go to the idle setting and an alarm will occur (Stuck in Critical). During a start-up routine if the Speed PID cannot accelerate the unit though a programmed band within a calculated length of time, a “Stuck in Critical” alarm will be issued and the speed set point will instantly return to idle. The “calculated length of time” is a value of five times the length of time it should normally take to accelerate through the band (based on the “Critical Speed Rate” setting). If the “Stuck in Critical” alarm occurs on a regular basis, it may be indicating that the “Critical Speed Rate” is set too fast for the turbine to respond to. Critical speed bands are defined in the configure mode. All critical speed band settings must be set below the ‘Min Governor Speed Set Point’. A configure error will occur if an idle set point is programmed within a critical speed band. The rate in which the speed set point moves through a critical speed band is set by the ‘Critical Speed Rate’ setting. The ‘Critical Speed Rate’ setting should be set at but no higher than the turbine’s rated maximum acceleration rate.

No Start Sequence 

If neither, the Idle/Rated or Auto Start Sequence functions are programmed, the speed set point will ramp from zero to the minimum governor set point at the ‘Rate To Min’ setting rate. Critical speed bands cannot be programmed with this configuration.

The idle/rated function gives an operator the ability to move between a programmed idle speed and a programmed rated speed at a configured rate. The selection of idle or rated speed set point positions can be made through the front panel keypad, through remote contact inputs, or through the Modbus communications links. The idle/rated function can also be programmed as a ramp-to-rated function only. If the 505’s Idle/Rated function is programmed, once a ‘START’ command is given, the 505 ramps turbine speed from zero to the programmed Idle setting, then waits for a command from the operator to ramp turbine speed to the “Rated Speed” setting. When deselected, the turbine speed ramps down to the application’s Idle Speed setting (as defaulted in the Service Mode).

Ramp to Rated Feature 

The Idle/Rated function can be changed to a “Ramp to Rated” function (see Service Mode). With this configuration, the speed set point holds at the idle speed setting until a Ramp-to-Rated command is given. Upon command the speed set point will accelerate to the Rated speed set point, however, it will not ramp back to the idle speed setting. When Rated is de-selected, the speed set point stops as opposed to returning to Idle. When this configuration is used, there is no Ramp- to-Idle option; it is not used. If Rated is de-selected while in a critical speed avoidance band (using Ramp to Rated only feature), the speed set point will stop at the top end of the avoidance band. If the Ramp to Rated function is stopped/halted using a raise or lower speed set point command, the set point will continue to the upper limit of the band if a Raise command was used or will reverse direction to the lower limit of the band if a Lower command was used

If Idle is selected while in a critical speed avoidance band (not using Ramp to Rated only feature), the speed set point will return to the Idle set point, continuing to move at the critical avoidance rate while within the band. The speed set point cannot be stopped within a critical speed avoidance band. Attempting to stop the ramp to rated while in a critical band will continue the speed set point to the upper limit of the band if a Raise command was used or will reverse direction to the lower limit of the band if a Lower command was used.