Starter PanelsTapped50/65/80%High inertia
Auto Transformer Starter Panel
Starts the motor on a reduced voltage tap, then steps up to full. Gives more torque per amp than star-delta, which is what a heavy start needs.
Rating plate
Auto Transformer Starter Panel
- Standard
- IEC 60947-4-1
- Motor rating
- 30 kW to 400 kW
- Taps
- 50%, 65%, 80% of line voltage
- Starting current
- 1.7 to 4 × FLC, depending on tap
- Starting torque
- 25% to 64% of direct-on-line torque
- Transition
- Closed (Korndörfer), no supply interruption
- Duty
- Typically 3 starts/hour, 15% cyclic rating
- Degree of protection
- IP42 to IP54
Specifying this panel
The auto-transformer wins where star-delta cannot: at the 65% tap it draws about 42% of DOL current but still delivers 42% of DOL torque — a far better torque-per-amp trade than star's 33%/33%.
Korndörfer (closed) transition keeps the motor energised throughout, so there is no re-acceleration spike. It is the reason this starter survives on high-inertia loads.
The transformer has a cyclic rating, not a continuous one. Repeated starts inside the cooling period is how these are destroyed.
Built for
- Large fans and blowers with high inertia
- Ball mills and crushers
- Loaded conveyors
- Motors on a supply too weak for star-delta
Fitted with
The assembly is ours; the switchgear inside it is genuine, authorised-channel product from the makes you specify.
Starter Panels
Other panels in this family.
Built to the same standard, and able to share a lineup with this one.
Direct on line · ≤ 7.5 kW
DOL Starter Panel
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Y-Δ · 1/3 current · ≤ 280 kW
Star Delta Starter Panel
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Variable speed · 0.37–400 kW
VFD Panel
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Ramped · Bypassed · ≤ 400 kW
Soft Starter Panel
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Next step
Send us the single-line.
A drawing, a load list or a BOQ is enough to start. You'll get the ratings checked against the actual fault level, a general-arrangement drawing to approve, and a fixed price.