Power Electronics / Power Management


Points to consider when running power supplies from portable generators

23 October 2019 Power Electronics / Power Management

With outdoor events like concerts, events and festivals now involving multiple, large display screens and a host of other electronics, portable diesel generator sets are often used to provide the AC power in temporary locations.

With outdoor events like concerts, events and festivals now involving multiple, large display screens and a host of other electronics, portable diesel generator sets are often used to provide the AC power in temporary locations. One question we get asked quite frequently is about the suitability of running a power supply from a portable generator set. We tend to think of voltage waveform distortion and voltage noise spikes, but actually there are other issues that are of concern.

Figure 1. Generator voltage overshoot with load change.

A backup generator for a factory would normally be powering multiple load types, consisting of heating, lighting, machinery and office equipment. It would be unlikely that the loading on the generator would undergo sudden major changes. At an outdoor event though, this may happen – particularly at the end of a song or during a break in the event schedule. If this occurs there could be a brief, but substantial rise in the AC voltage when the generator suddenly sees a very light load.

Initially manufacturers specifying the use of generators had to rely on local country standards, but these did not always specify voltage and frequency deviations – just the ability to be capable of accepting and recovering from a full load step. Stability and response times are now categorised under the ISO 8528 (BS7698) standard with four performance standards listed in ISO 8528-1-7 for governor regulation.

Figure 2. TDK-Lambda’s RWS-B series.

Class G1 is used for applications where the connected loads only require the basic parameters to be specified. This includes general-purpose applications like lighting and electrical loads.

Class G2 is required for applications where regulation is not that critical and temporary deviations are acceptable. Lighting systems, pumps, fans and hoists have some tolerance to frequency and voltage.

Class G3 is for applications where the equipment demands are moderately severe and includes telecommunications equipment and thyristor-controlled loads.

Class G4 is required for applications where the demands are extremely severe. This typically includes data-processing and computer equipment.

The limits for these devaluations are shown in Table 1.

Table 1. Comparison of ISO 8528 generator classes.

Examining the impact of these voltages on various regions we get the data shown in Table 2. Most AC-DC power supplies are rated for 85 or 90 V a.c. to 264 V a.c. operation, but a number of manufacturers are now offering products that will accept 300 V a.c. for 5 seconds. These products tend to be enclosed in a metal chassis, like TDK-Lambda’s RWS-B series, and are targeted at industrial applications.

Table 2. Impact of generator classes in different regions.

From the tables above, products rated for 300 V a.c. for 5 seconds can be used on Class G3 generators, and depending on the extent of the anticipated load changes, can probably be used with Class G2. Open-frame power supplies like TDK-Lambda’s ZMS100 tend not to have the 300 V a.c. peak rating. This is because they are usually used in ITE (Information Technology Equipment) systems, where the end customer will request a Class G4 generator.

This does raise issues of concern, as mentioned earlier...Designers of equipment who anticipate their product being used by diesel generators, should consider using an industrial AC-DC power supply that has a 300 V a.c. peak rating.

Figure 3. TDK-Lambda’s ZMS100 series.

Manufacturers of the end systems should specify what class of generator their products should be used with. If they do see equipment failures when used with generators, they should question what class was used. Often the choice of generator will be that of the event organiser, who may lean towards the lowest cost.

For more information contact Tobie Muller, Accutronics, +27 11 782 8728, tmuller@accutronics.co.za, www.accutronics.co.za


Credit(s)



Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

Boost charger for 2-cell series lithium-ion battery
29 July 2020, NuVision Electronics , Power Electronics / Power Management
The MP2672 from Monolithic Power Systems is a highly integrated, flexible switch-mode battery charger IC for a lithium-ion battery with two cells in series, which is used in a wide range of portable applications. When ...

Read more...
LED dimming signal interface controller
29 July 2020 , Power Electronics / Power Management
The AL8116, made by Diodes Incorporated, is a flexible dimming signal interface controller that can convert the three different inputs of dimmer types including 0-10 V d.c. linear dimming, 0 to 100% duty ...

Read more...
USB Type-C charging controllers
29 July 2020, Avnet Silica , Power Electronics / Power Management
Designers can overcome the challenges of implementing USB-C Power Delivery (PD) with the MAX77958 USB-C PD controller and the MAX77962 28 W buck-boost charger from Maxim Integrated Products. As portable ...

Read more...
All-in-one DC UPS units
29 July 2020, Current Automation , Power Electronics / Power Management
Thanks to the range of all-in-one DC UPS units from ADEL System, it is possible to optimise power management for many applications. The available power is automatically allocated between load and battery; ...

Read more...
Power supplies for flicker-free LED driving
31 August 2020, Current Automation , Power Electronics / Power Management
A feature of Mean Well’s new LDC-35/80 family of LED drivers is the stabilisation of the output power. The specified operating mode ensures the constancy of the output power when the source operates within ...

Read more...
Healthcare, industrial and ITE power supplies
31 August 2020, Vepac Electronics , Power Electronics / Power Management
New from XP Power is the ECH450 series of compact, high-efficiency power supplies available in open-frame or a range of enclosed formats. Delivering 250 W when convection cooled and the full 450 W when ...

Read more...
Flicker-free LED driver with 3-in-1 dimming
29 July 2020, Current Automation , Power Electronics / Power Management
A feature of Mean Well’s new LDC-35/80 family of LED drivers is the stabilisation of the output power. The specified operating mode ensures the constancy of the output power when the source operates within ...

Read more...
New electromagnetic solutions range from Accutronics
29 July 2020, Accutronics , News
Accutronics has been appointed as the reseller for the Electromagnetic Integrated Solutions (EIS) range of products from API Technologies. APITech offers a complete line of coaxial EMI solutions, ...

Read more...
MOSFET half-bridge power stage
30 June 2020, Altron Arrow , Power Electronics / Power Management
Vishay Intertechnology introduced a new 30 V n-channel MOSFET half-bridge power stage that combines a high-side TrenchFET MOSFET and low-side SkyFET MOSFET with integrated Schottky diode in one compact ...

Read more...
Programmable electronic DC loads with energy recovery
30 June 2020, Vepac Electronics , Power Electronics / Power Management
Elektro-Automatik’s new series of electronic DC loads with energy recovery to mains, called EA-ELR 9000 HP, is an advancement of the series EA-ELR 9000. It offers a wider AC input range for operation ...

Read more...