Why Does a Production Line Need Backup Power?
In many countries that import production lines from China, the public electrical grid is not stable around the clock. Even a few minutes of power loss can shut down an entire line, and in industries such as plastics, metalworking, and food processing it can ruin a full production batch or damage expensive molds. This is why choosing a backup generator should be part of the machinery import plan from the start, not a decision made after the line arrives and outages start recurring.
Steps to Calculate the Right Generator Size
1. Calculate the Total Electrical Load in kW
Start by adding up the power rating listed on the nameplate of every machine on the line (motors, pumps, heating systems, PLC control panels, industrial lighting). This figure is the nominal load — a starting point, not the final number used to select the generator.
2. Calculate the Starting Surge
Electric motors, especially large compressors and pumps, draw 3 to 7 times their rated current the instant they start. If the line has several large motors that could start simultaneously, the generator must be sized for the highest expected starting load, not just the steady operating load.
3. Apply a Safety Factor
After adding the operating load and the starting load, a safety margin of 20% to 30% is typically added to accommodate future line expansion or additional auxiliary machines.
- Continuous operating load of all machines combined
- Highest possible simultaneous starting load
- 20%-30% safety factor for future expansion
- Site altitude and ambient temperature, since both affect the generator's actual output
Generator Types and Which One Fits Your Line
| Generator Type | Best For | Note |
|---|---|---|
| Diesel | Heavy loads and long continuous operation | Most common in factories, well-known maintenance, spare parts widely available |
| Natural Gas | Factories near a gas grid, cleaner operation | Lower running cost but requires gas line infrastructure |
| Dual-Fuel | Factories wanting flexibility between diesel and gas | Higher upfront cost in exchange for operational flexibility |
Common Mistakes When Choosing a Generator
- Sizing the generator on operating load alone without accounting for starting surge
- Ignoring the effect of site temperature and altitude on actual generator output
- Leaving no margin for future expansion, forcing a whole new generator purchase after adding just one machine
- Overlooking the match between generator frequency (50Hz or 60Hz) and the production line's designed frequency
Golden rule: size the generator for the highest possible operating moment of the production line, not the average daily consumption.
Integration with the Automatic Transfer Switch (ATS)
Choosing the right generator size is not enough on its own; pairing it with an Automatic Transfer Switch (ATS) ensures a smooth transition between the public grid and the generator within seconds, which is critical for protecting sensitive PLC systems and HMI screens from the shock of sudden restarts. It is also advisable to run an actual load test on the generator after installation rather than relying solely on the manufacturer's catalog specifications.
If you are planning to import a new production line and need help calculating the right generator size or sourcing reliable suppliers for backup power systems, get in touch with our team and we will help you build a complete power plan for your factory.