dreizler® frequency -
Speed control of the burner blower

Patent No. 199 21 045




Run the motor at full speed and control the speed by using the brakes? No one drives a car in this way. Certainly, the inter-relationship between burners and their combustion air blowers is not as simple as this but the burden of the message remains the same: it is much more economical to provide only that amount of air which the current burner function requires!


Power saving

The operator of the plant can save 80% of his consumption of electricity if the frequency burner runs at a lower speed value when unter partial load - and the surrounding area benefits from the reduction in noise level.


What are the facts?

The current consumption of an ideal blower is proportional to the third power of its speed. If the speed are reduced by half, the current consumption is reduced to one-eigth of its previous level. The effect is even more drastic in terms of noise level: it is difficult to hear a dreizler marathon® burner when the blower operates at half maximum speed - and most modulating burners spend the greater part of their working life running under partial load conditions!



Red curve, burner without speed control:

A burner with a thermal capacity of about 3000 kW has a 5,5 kW fan motor. However this power is required only when the burner is operating a full capacity.

A burner without speed control, i.e. one with a motor running at constant speed but with a throttling device to control the volume of air uses the same aomunt of electrical power over almost all the prerformance range. The level of current consumption falls only a little when the burner operates at partial load.

Blue curve, dreizler® burner with frequency

Things are very different with the dreizler® frequency burner; here the speed of the motor is adjusted by means of a frequency inverter to suit the combustion conditions. Here it means a current consumption of only 0,75 kW at a burner capacity of 20%.

In comparison with a conventional burner of the same capacity the dreizler®
frequency burner saves around 5 kW of electrical power every hour it runs under these conditions. 


And what does that mean at the end of the year?

To determine this it is necessary to know how long the burner operated under what conditions. Multiplying this number of hours by the current consumption for the particular load conditions establishes the current consumption for a quite special load profile.

In our example with a typical load profile for heating or hot water, an assumed electricity price of 0,1 €/kWh and a total of 4.000 operating hours per year this represents a savings potential of around 13100 kWh or about 1.400,- € per annum.

Load profile



The frequency invertor is built into the burner and delivered ready wired up. No special electrical activity is required for its operation. 

The frequency invertor lies at the motor side on the burner and at the right one invisibly under the hood of the burner. EMV tests confirm the quality of the FU and its preparation.

How much would a dreizler® frequency burner save in your plant? We would be pleased to calculate this on receiving your data.

Under this link you will find a PDF-form which you can send to Fax no. 07424-700990 or by mail to technik(at)dreizler.com. We look forward to hearing from you.

dreizler® frequency: Saves current and operates quietly.  

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Walter Dreizler GmbH Wärmetechnik
Max Planck Strasse 1-5 | 78549 Spaichingen | Tel. +49-(0)7424-70090 | Fax. +49-(0)7424-700990