dol starter used up to how much hp, Answer: A DOL (Direct-On-Line) Starter is generally used for small induction motors up to about 5 HP (3.7 kW) — though the exact limit depends on voltage level and local utility rules.
Here’s the detailed explanation 👇
Typical Motor Power Range:
| Motor Power (HP) | Motor Power (kW) | Common Applications |
|---|---|---|
| 0.5 – 3 HP | 0.37 – 2.2 kW | Fans, small pumps, mixers |
| 3 – 5 HP | 2.2 – 3.7 kW | Compressors, blowers, conveyors |
| Up to 7.5 HP (max) | Up to 5.5 kW | Only if supply network allows (strong supply system) |
Why the Limit Exists:
- In DOL starting, the motor is connected directly to the supply line, so it draws a starting current 6 to 8 times its full-load current.
- For small motors, this high current is tolerable and doesn’t cause much voltage drop.
- For larger motors, it can cause a severe voltage drop, affecting other connected equipment — hence Star-Delta, Auto-Transformer, Soft Starter, or VFD are used.
In Simple Terms:
DOL starters are used for small motors up to 5 HP (3.7 kW).
Beyond that, Star-Delta or other reduced-voltage starters are preferred to limit high inrush current.