Trane VarioTrane TR1 2800 Series, Operating Instructions Manual

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This function ensures the highest possible switch fre-
quency without the frequency converter becoming
thermally overloaded. The internal temperature is the
actual expression of the degree to which the switch
frequency can be based on the load, the ambient
temperature, the supply voltage and the cable length.
The function ensures that the frequency converter
automatically adjusts the switch frequency between
f sw, min and f sw, max (parameter 411), see drawing.
When using the LC filter the minimum switch fre-
quency is 4.5 kHz.
PELV (Protective Extra Low Voltage) insulation is achieved by inserting galvanic isolators between the control
circuits and circuits that are connected to the mains potential. The TR1 is designed to meet the requirements
for protective separation by means of having the necessary creepage and clearance distances. These require-
ments are described in standard EN 50 178. It is also a requirement that the installation is carried out as described
in local/national regulations regarding PELV.
All control terminals, terminals for serial communication and relay terminals are safely separated from the mains
potential, i.e. they comply with the PELV requirements. Circuits that are connected to control terminals 12, 18,
19, 20, 27, 29, 33, 42, 46, 50, 53, 55 and 60 are galvanically connected to one another. Serial communication
connected to fieldbus is galvanically insulated from the control terminals, although this is only a functional
insulation.
The relay contacts on terminals 1 - 3 are insulated from the other control circuits with reinforced/double isolation,
i.e. PELV is observed for these, even though there is mains potential at the relay terminals.
The circuit elements described below form the safe electric separation. They fulfill the requirements for rein-
forced/double insulation and associated testing pursuant to EN 50 178.
1. Transformer and optical separation in voltage supply.
2. Optical insulation between Basic Motor Control and control card.
3. Insulation between the control card and the power part.
4. Relay contacts and terminals relating to other circuits on the control card.
PELV insulation of the control card is guaranteed under the following conditions:
- TT network with maximum 300 Vrms between phase and earth.
- TN network with maximum 300 Vrms between phase and earth.
- IT network with maximum 400 Vrms between phase and earth.
In order to maintain PELV all connections made to the control terminals must be PELV, e.g. thermistor must be
reinforced/double insulated.
TR1 2800 Series VFD 115
Temperature-dependent Switch Frequency
Galvanic Isolation (PELV)
All about TR1 2800 Series VFD