Quarry power factor correction fails and nothing trips
Quarry power factor correction can lose a capacitor step and nobody sees it. The crusher runs, the screens run, the switch room looks fine. The only sign is a bigger kVA figure on the invoice.
Ergon Energy Retail says sites with a power factor near 1 pay less on a kVA tariff, and less efficient sites pay more. Every dead step puts its kvar back on your supply.
The crusher start sets the peak. Primary, secondary and screens kick in together, and the demand charge follows the highest half hour.
- A blown step fuse or a burned contactor.
- A capacitor that has lost capacity from heat and dust.
- A controller left in manual after a visit.
Today versus with step alerts
| Topic | Today | With monitoring |
|---|---|---|
| Finding a dead step | A glance at the controller, or the invoice | A text naming the step, same day |
| Controller alarm | Often wired to nothing | Wired in, texts maintenance after 10 minutes |
| Between inspections | Thermal imaging once or twice a year | Step current checked every few minutes |
What we fit in the switch room
-
Step current sensors
One split-core clamp per capacitor step, fitted by a licensed electrician.
Reads every 1 to 5 min
-
Controller alarm input
Reads the controller's alarm relay, which is often wired to nothing.
Alert after 10 min
-
Panel temperature sensor
Sits near the fans and warns when dust or a dead fan cooks the bank.
Reads every 5 min
-
Site gateway
Collects every node's readings and passes them on.
Heartbeat check-in
-
Starlink backhaul
Gets the text out where the quarry has no mobile signal.
4G where signal's good
How quarry power factor correction monitoring works
- 1
Sensors on each step
A split-core current sensor clips on one phase of each step cable. A dry contact reads the controller alarm.
- 2
Radio to the gateway
Each node sends small readings by LoRaWAN. The antenna sits outside the metal container, on a lead through a gland.
- 3
Starlink or 4G sends it out
The gateway uses Starlink where there's no mobile signal, or 4G where there is.
- 4
A text names the step
If a step is switched in but draws too little current, the people you nominate get the step number.
One dead step, with and without a text
Without monitoring
- Week 1Step 3 fuse blows. The controller still shows it on.
- Week 2Crusher starts push kVA up. Nobody notices.
- Month endThe invoice shows a higher kVA peak.
- Next visitSomeone opens the panel and finds the fuse.
With monitoring
- Week 1Step 3 fuse blows. Current drops to zero.
- Same morningText names step 3, expected 35 A, reading 0 A.
- That dayYour sparky isolates, proves dead and swaps the fuse.
- Month endThe peak stays where it should.
What lands on your phone when a step dies
Incomer kVA at crusher start
Dashboard view
- Step 3 current
- 0 A
- Incomer peak
- 498 kVA
- Panel temp
- 38 °C
On a quarry switch room
Your PFC bank probably sits in a dusty switch room or a steel container. We check the dust, the ventilation and where the radio can get out. Steel blocks the signal, so the antenna goes outside.
The same dead step is a problem on any big switchboard. See power factor correction failure alerts for the general version, and kVA demand warnings for watching the peak itself.
Running a recycling yard? Add compressed air leak alerts.
What it costs
We set a fixed price after a short scoping call or a site visit. It depends on how many steps and sensors, how far the switch room is from the gateway, and how it gets out. After handover, ongoing support is available as a plan.
Get a quote for PFC step alertsThe fixed price covers
- Current sensors on each step, plus the controller alarm input
- Gateway and Starlink or 4G backhaul
- Installation and electrical work under QLD Electrical Contractor Licence 1513082, with isolation and proving dead
- Alert set-up, and recording each step's expected current at commissioning
- An ongoing support plan: we keep it running, replace batteries and sensors and tune alerts
What this alert won't do
- It doesn't switch steps or control the bank. It tells you what's happening.
- Current on one phase won't show every capacitor fault. Switching and harmonics can set off false alarms until we tune it.
- The sensors are indicative, not metering grade. Use a revenue meter or your retailer's data as billing evidence.
- It adds to your capacitor protection, isolation procedures and inspections, and doesn't replace them. It isn't a certified safety or fire system.
- Readings stop if the gateway or backhaul is down. High voltage banks need a separate assessment.