Frequency converter 'frequency'
dreizler A 3001 E - 18.12.2015 | A 2064 - 1.14 | EN - 13.06.2014
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45.2 Allocation motor speed/air damper position
0 - 1000 ohm is selected via a potentiometer as voltage divider at a supply voltage of 0 - 10 V. On the air
damper actuator, a gradient in hertz/volt change is selected at the frequency converter, which controls the
allocation of angle / air damper to speed / motor.
Fixed points are:
NOTICE:
This is the preset factory setting!
NOTICE:
For reasons of stability, lower motor speeds should not be run. Otherwise the frequency converter would
run after the servomotor.
45.3 Monitoring
Compliant with EN 676, one of the safest types of mixture control is provided with the gas/air ratio control.
It offers benefits for pressure monitoring in the combustion chamber, reactions to boiler contamination, and
monitoring options in burners with fuel quantity regulation depending on the remaining generation of air
pressure. The burner reacts to contamination with a throttling of the fuel quantity for continued safe and
clean functionality.
45.4 Burner configuration
The Frequency converter and the marathon
®
burner are preconfigured ex works. There is no need for con-
figuring the frequency converter on-site. The burner requires a configuration of the gas/air ratio control via
the gas combination valve.
A delayed run-up after the burner start-up may be required to stabilise and heat the burner head. For this
purpose, ARZ timing is used, which is a tried and tested method used for LOW NOx ARZ burners.
NOTICE:
Record the servomotor position at 100%, 50% and at MIN load, as well as the relevant control frequencies
sent from the frequency converter to the motor in the measurement log.
The mode of action of 'frequency' is analog to that of an electronic motor speed control via micro processors
45.5 Regulation and modulating function of 'frequency' burners
The gas operation in gas and dual fuel burners with blower can be regulated in a modulating manner by
means of 'frequency' motor speed control. Functionality is controlled by means of a PID temperature or
steam pressure controller with DPS output. Control is effected either via DDC regulation or a boiler control-
ler. Motor speed and damper position are actuated linearly across the entire configuration range depending
on load.
MAX load
Air damper
Motor speed
Frequency
100%
90°
3000 rpm
50 Hz
25%
20°
>1500 rpm
25 Hz