See Chapter 5 of this Volume for all 505 service panel messages.
Overspeed Test Function
The 505’s Overspeed Test function allows an operator to increase turbine speed
above its rated operating range to periodically test turbine electrical and/or
mechanical overspeed protection logic and circuitry. This includes the 505’s
internal overspeed trip logic and any external overspeed trip device’s settings
and logic. An Overspeed Test will allow the control’s speed setpoint to be
increased above the normal maximum governor limit. This test can be performed
from the front panel of the control or with external contacts. This test is not
permissible through the Modbus.
An overspeed test is allowed only under the following conditions:
The Speed PID must be in control
The Auxiliary, Cascade, and Remote Speed Setpoint PIDs/functions must
be disabled
If configured for a generator application the Generator breaker must be
open.
The Speed Setpoint must be at the, “Max Governor Speed” setting.
If the ‘OSPD’ key is pressed or an external Overspeed Test contact is closed (if
programmed) and the above conditions are not met the control will display a
“Overspeed Test/Not Permissible” message.
An overspeed test can be performed through an external contact, if the
‘Overspeed Test’ function is programmed to a ‘Contact Input # Function’ setting.
When configured this contact performs the same function as the 505’s front panel