13 • Recommended Wiring Scheme
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4.3.9.2 Notes on “Inside Delta” connection
• “Inside Delta” requires 6-wire to the motor.
• Wrong motor connection will cause serious damage to the motor windings.
• When installing the RVS-DX “inside delta” it is highly recommended to use a contactor in
series to the RVS-DX or upstream (after motor protection) in order to avoid a destruction
of the motor in case of a shorted SCR in the RVS-DX.
• The sinusoidal shape of the current is imperfect (since each phase is separately fired and
not influenced by other phase firing).
As a result, higher harmonic content is incurred (THD), which can be as high as twice the
THD value as in the standard “In-Line”.
• Higher motor heating is expected for the same motor size (due to the higher THD).
• Phase sequence must be correct; otherwise, “Phase Sequence fault” will trip the starter
immediately (without any damage).
• Higher torques can not be obtained
• Factory preset - features and functions when “Inside Delta” mode is configured:
o No Pulse Start.
o No curve selection (Curve 0 !! only).
o No Slow Speed
o No Phase sequence “Off” mode
Note :
For a high starting torque process, it is recommended to use the starter in the “In Line” connection.
1. It is highly recommended to use a contactor in series to the RVS-DX
or upstream (after motor protection) in order to avoid a destruction of the
motor in case of a shorted SCR in the RVS-DX.
2. If Contactor is connected Inside the Delta, motor terminals are “live” (full
(2) C2 is an “Inside Delta” contactor.
(3) U1-U2, V1-V2, W1-W2 are motor’s windings.
(4) L1-U, L2-V, L3-W are RVS-DX controlled phases.
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