ETC offers a wide choice of dedicated servo motors ranging from 4-40Nm in size for use with the ETC6000. These servo motors accurately position air dampers and fuel valves to a resolution of 0.1º over a 90º stroke, allowing fuel:air ratio profiles to be reliability repeated. Using a servo motor for each variable component of a burner control system, such as the secondary air damper, gas & oil metering valves, eliminates the need for complex mechanical linkages.
Hysteresis and backlash have traditionally been inherent weaknesses of mechanical linkages, joints work loose and become worn preventing repeatable positioning especially when travel is in opposite directions. These inaccuracies not only reduce combustion efficiency, resulting in more fuel usage and emissions, but also mean that the combustion engineer will have to set the combustion profile further from the stoichiometric point during commissioning to take these variables into account.
Should larger servo motors be required, there is the option of installing third party drives using a ETC CANbus servo interface – details available on request.
The ETC6000 servo motors all reside on a single CANbus. This provides benefits that include: –
- Less physical wiring and wiring containment.
- Fewer terminations. (Previous products have one channel
per servo motor.)
- Up to 10 servo motors per system.
- Intelligent fault reporting such as loss of communication
and positional errors.
- Each servo motor has unique serial number, this increases
system integrity; replacement drives can only be recommissioned
by entering unique controller passcode.
Unusual and unique applications can be addressed such as.
- Temperature trim.
- Twin-firing combination.
- Complex boiler sequencing.
- Water pump/valve control.
- Draught control.
- ‘Service due’ indications etc.