Moeller - Multi speed switches of three-phase motors - Tapped winding, non-reversing, 2 speeds

Tapped winding, non-reversing, 2 speeds [t-head1-first]

Multi-speed contactors UPSDAINL [t-head3]

Star-delta starting at low speed

Fuseless [t-head3]

Without overload relay

Rating of switchgear
Q1, Q17 = I₁

(low speed)
Q2, Q21 = I₂

(high speed)
Q19, Q23 = 0,5 × I₂

With fuses and overload relays

Rating of switchgear
F2, Q17 = I₁

(low speed)
F21, Q21 = I₂

(high speed)
Q19, Q23 = 0,5 × I₂
F1 = I₂

Overload relays F2 and F21 are not used on multi-speed contactors without motor protection. If F2 and F21 cannot be protected by a common fuse, then use circuit on → figure.

Motor windings → section Motor windings.


		Circuit Low speed selected only from zero, high speed only via low speed without actuation of the Stop button. Three-way pushbutton I: Low speed (Q17, Q19) 0: Stop II: High speed (Q21, Q19, Q23)


Q17: Mains contactor, low speed K3: Timimg relays Q23: Star contactor	Q19: Delta contactor Q21:Mains contactor, high speed

Function [t-head3]

Actuation of pushbutton I energizes the coil of star contactor Q23. Its normally open contact 13-14 energizes the coil of contactor Q17. The motor runs in star at low speed. The contactors are maintained via auxiliary contact Q17/13-14. At the same time, timing relay K3 is triggered. When the set time has elapsed, K3/15-16 opens the circuit of Q23, which drops out, the coil of delta contactor Q19 is energized and maintains itself via Q19/13-14. The timing relay is de-energized via normally closed contact Q19/32-31.

The motor runs in delta at low speed. Actuation of pushbutton II de-energizes the coil of Q17 and via Q17/22–21 energizes the coil of Q21. This state is maintained by Q21/43–44: The coil of star contactor Q23 is re-energized by normally open contact Q21/14–13. The motor runs at high speed.
Pushbutton 0 (= Stop) effects disconnection.