Generator manufacturers know how difficult it can be for operators to recognize and react to problems. Issues with the load, voltage, phase and power factor can all contribute to instability and overheating, and ultimately damage the generator or the equipment connected to it.
Many generator manufacturers integrate volt, amp and frequency meters into their generators with alarms to alert operators to issues before they become a problem. However, generator failures are still far too common.
The Challenge
Many generator manufacturers are currently using analog meters and a three-position phase selector switch as mechanisms for operators to detect issues. This involves a minimum of three meters to measure volts, amps and frequency. In addition, the operator must use a switch to check measurements on each phase.
While these solutions work on a technical level, they often do not provide the desired outcome: preventing a generator failure. This happens for two primary reasons:
Generator Location
Generators are engine driven and powered by diesel, gasoline, or natural gas. The resulting noise and harmful emissions that generators produce mean that the typical generator is isolated and located in a place removed from people. Even audible alarms from the typical generator would not be heard by anyone, much less a qualified operator.
Lack of a Dedicated Operator
Because generators are not production equipment, they rarely have an assigned operator. As a result, the responsibility for managing a generator can fall to a facilities manager or maintenance person with many other duties. These operators are infrequently standing at the generator, and even more infrequently monitoring alarms.
The result of these factors is that the person who could mitigate an issue based on an alarm is rarely able to react in time. And when problems go unnoticed, failures can be catastrophic.
- Downtime for generators typically means complete loss of power, whether it’s in a disaster situation or remote area.
- Damage to the generator can often result in damage to the equipment connected to it, and costly maintenance and repair.
- Costs add up for repairs, replacements, and lost work in progress for the customer.
- Harm to People or loss of life can result when critical life support equipment goes offline in the severest of situations.
It’s clear that the current technologies for detecting and communicating problems are simply not solving the problem of preventing critical failures, and both customers and manufacturers are paying the price.
The Solution: Communications
The key to making meters and alarms more effective is to incorporate communications into the design. With communications, operators can remotely monitor meters from any device such as a phone or computer, and operators can see alarm conditions in real time on those devices. Depending on the customer’s set-up, the alarm conditions can be pushed out to the network and the operator can be alerted without needing to monitor their screen or phone.
Modbus is a data communications protocol that allows the user to download all the available data from a device via an ethernet or RS485 connection. In the case of a generator, this data can include volt, amp and frequency on all phases, in addition to the necessary parameters for alarm conditions.
The data can be used to monitor conditions in real time or to collect trends over time, which can be used to predict and prevent failures.
How to Implement Modbus
Taking advantage of Modbus is an easy step for generator manufacturers. Requirements include:
- A digital power meter with Modbus capability (see How to Choose a Modbus Capable Meter)
- Generator usage in an environment with network connectivity
- A Cat 5 ethernet connection near the generator. There may be distance limitations, so check with your IT professional.
If you meet these requirements, setup is easy and starts with mapping. There are some standard off the shelf Modbus reading software packages available that will read the parameters from the device when a request is sent. To configure, set a baud rate and the stop bits and parity that your system is compatible with.
The bulk of the work for Modbus setup is in mechanical design to physically install the digital meter. Electrical design is also needed to convert wiring from the old meter to a new one and network expertise. To fully integrate the data for data logging or trend analysis purposes, you may need assistance from your engineering or IT department.
Documentation and training for your customers will be important because getting the generator on their network will involve them. This is a one-time task that will require IT or engineering assistance. Network configuration involves setting up the generator to communicate with the network. Most end customers will have this capability in-house. Modbus is a standard protocol so integrating a power meter into the network will be no different than any other Modbus device they have added. Deciding what to do with the data will be up to the individual collecting it.
