
KT-210-420
1 Introduction
Frequency inverters (FI) are used to adapt the com-
pressor capacity to the actual cooling demand of the
system. The motor speed of the compressor is step-
lessly adjusted by a frequency inverter over a wide
range. During peak load periods, operation in a fre-
quency band above supply frequency can increase the
compressor capacity by up to 70% compared to opera-
tion at supply frequency (if voltage increases propor-
tionally to the frequency). For the
BITZER ECOLINE VARISPEED types, compressor and
FI are precisely matched to each other and the operat-
ing parameters of the frequency inverter are preset in-
dividually for each compressor type.
This Technical Information describes the frequency in-
verter .F1 and its electrical connection. For further in-
formation and safety instructions regarding the com-
pressor refer to the Operating Instructions KB-104. The
frequency inverters have been built in accordance with
state-of-the-art methods and current regulations. Partic-
ular importance has been placed on user safety. The
Operating Instructions KB-104 and this Technical In-
formation must always be kept available near the refri-
geration system!
2 Safety
2.1 Authorized staff
All work done on compressors, frequency inverters,
electronic accessories, and refrigeration systems may
only be performed by qualified and authorized staff who
have been trained and instructed accordingly. The local
regulations and directives with respect to the qualifica-
tion and expertise of the skilled personnel shall apply.
2.2 Residual risks
Frequency inverters may present unavoidable residual
risks. That is why any person working on this device
must carefully read these Operating Instructions!
The following rules and regulations are mandatory:
• relevant safety regulations and standards (e.g.
EN378-2 and EN60204-1),
• generally accepted safety rules,
• EU directives,
• national regulations.
2.3 Safety references
are instructions intended to prevent hazards. Safety ref-
erences must be stringently observed!
NOTICE
Safety reference to avoid situations which may
result in damage to a device or its equipment.
CAUTION
Safety reference to avoid a potentially hazard-
ous situation which may result in minor or mod-
erate injury.
WARNING
Safety reference to avoid a potentially hazard-
ous situation which could result in death or seri-
ous injury.
DANGER
Safety reference to avoid an imminently hazard-
ous situation which may result in death or seri-
ous injury.
2.3.1 General safety references
When working on the electrical system and the fre-
quency inverter:
DANGER
Life-threatening voltages inside the FI housing!
Contact can lead to serious injuries or death.
Never open the FI housing in operation!
Switch off the main switch and secure it against
being switched on again.
Wait for at least 5 minutes until all capacitors
have been discharged!
Before switching on again, close the FI housing.
CAUTION
Surface temperatures of more than 60°C or be-
low0°C.
Risk of burns or frostbite.
Close off accessible areas and mark them.
Before performing any work on the compressor:
switch it off and let it cool down or warm up.
When working on the refrigeration system:
WARNING
The compressor is under pressure!
Serious injuries are possible.
Depressurize the compressor!
Wear safety goggles!