Updated
Identification
How to Read a Generator Data Plate
A generator data plate typically lists the make, model and serial number, the rated kVA and kW, voltage, current in amps, frequency (50 Hz in South Africa), phase, power factor (usually 0.8 on three-phase sets) and separate standby and prime ratings. The engine has its own plate, and its manual uses that engine model for parts and service intervals.
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- A photo is enough to start
- Generator plate and engine plate
- kVA, kW and duty read correctly
- Onsite across Gauteng
What the label is for
Which plate am I looking at?
Your generator has up to three labels. The generator data plate, usually on the alternator or the canopy, describes the electrical machine: maker, model, serial number, kVA, voltage, frequency and phase. The engine plate, often on the block, gives the engine model and serial. The controller shows its own model on the fascia. Photograph each one separately so the details stay clear.
Common fields are manufacturer, model, serial number, kVA, kW, voltage, current in amps, frequency in hertz, phase, power factor, rpm, a standby rating, a prime rating and a date. Read what is printed. If a line is missing, tell us, and we work it out from the model rather than guess.
We ask for the photo so your visit matches your set: the right service, the right fault diagnosis and parts that fit that alternator or engine. Send the generator plate, the engine plate if you can find it, a controller photo and a photo of any alarm, and we arrange the visit from there.
Fields you may see
Make, rating and duty
Manufacturer, model and serial
The make and model identify the brand and type of set. The serial number identifies your machine. They can sit on different plates.
kVA, kW, voltage and amps
These are the electrical rating. kW = kVA × power factor, so a 100 kVA set at 0.8 gives 80 kW. Amps are the current at the stated voltage.
Frequency, phase and power factor
South African sets run at 50 Hz. Phase is single or three. Power factor, typically 0.8 on three-phase ratings, is what makes kVA and kW differ.
RPM and duty ratings
Engine speed and, where printed, standby and prime kVA. Two kVA figures mean two duties: the higher standby figure applies only to outage use. Some plates show a manufacture date.
Alternator plate and reseller labels
On many sets the alternator carries the electrical rating and the canopy carries a reseller label. If they disagree, photograph both and tell us which is which.
Why we ask for the photo
It stops a wrong parts order and a wrong kVA assumption. Send it with your fault description and we arrive prepared.
Worked example: reading a real rating
Here is how the published ratings for one real 50 Hz diesel set, the Cummins C330D5, read field by field. Your own plate may show fewer fields, so read what is printed on it.
| Field | Example value | What it tells you |
|---|---|---|
| Model | C330D5 | The generator set model. Use it to find the specification sheet. |
| Engine | Cummins QSL9-G5 | The engine model, which sets the service parts and intervals. |
| Frequency | 50 Hz | Matches the South African supply. |
| Standby rating | 330 kVA / 264 kW | The most it delivers during outages. |
| Prime rating | 300 kVA / 240 kW | The most it delivers as a main supply with a varying load. |
| Continuous rating | 249 kVA / 199 kW | The figure for a steady load around the clock. |
| Power factor | 0.8 (264 ÷ 330) | The link between kVA and kW. |
Source: Cummins: C330D5 generator ratings. Our standby vs prime guide explains the three duty ratings.
Common Questions
Questions about generator data plates
What is on a generator data plate?
Typically the make, model and serial number, rated kVA and kW, voltage, current, frequency, phase, power factor and often separate standby and prime ratings. The engine has its own plate with the engine model and serial.
Does every plate show kW and kVA?
No. Some show kVA only; others show both, plus the power factor. If only kVA is printed, multiply by the power factor, typically 0.8, to get kW.
Where is the plate?
Usually on the alternator end or on the canopy frame. The engine plate is on the engine. If you cannot find it, photograph the controller and the canopy badges instead.
The plate is painted over. What then?
Send what you can still read, plus the controller and any engine stamping you can see without dismantling the set. Often that is enough to identify the set.
Why do you want the engine plate as well?
Service parts and intervals follow the engine. The generator plate gives the electrical rating. Each answers a different question.
What should I send with a fault?
The generator plate, the engine plate if relevant, a controller photo and a photo of the alarm text.
Can the plate tell you the fault?
It identifies the machine. The fault shows in what the set is doing, so send both the plate and a description of the symptom.
Still unsure what the fault is? Call or WhatsApp 082 057 4605 for onsite diagnosis.
Service Areas
Onsite visits across Gauteng
We come to your generator anywhere in Gauteng, 24/7. Choose your region for local suburbs, call-out details and the faults we see most there.
What to send before we attend
These details help us plan the visit and bring the right parts. Send what you can on WhatsApp; if you can’t find the model number, we still book the visit.
- Location
- The suburb or site, so the visit can be booked in the right area.
- Make and model
- The generator brand and model, if they are known.
- kVA
- The size printed on the data plate.
- Fuel type
- Diesel, petrol, LPG, natural gas, or dual-fuel.
- Controller model
- The module name on the panel, when it is visible.
- Fault or alarm
- What the set does, and any text on the screen.
- Photos
- The generator, the data plate, and the controller or alarm. Send these on WhatsApp.
Book a Visit
Send the plate photos
Generator plate, engine plate if you can see it, and the controller if there is an alarm.
- Call
- 082 057 4605
- Message us on WhatsApp
What happens next
- We reply with questions about the generator, or to book a visit.
- A technician comes to you. For a breakdown we arrive within 1 hour.
- The fault is diagnosed on site and you get a written quote. No work starts until you accept it.
Charlie, lead technician: Degree in Mechanical Engineering, Degree in Electrical Engineering, Diesel Plant Fitter. Generator specialists since 2000.