Safety Advice
Backroom Ltd shall not to be held accountable in any way if you choose to ignore the following plain, simple and sensible advice:
- Electricity is invisible. You can not see it, hear it or smell it.
- Never open or otherwise interfere with any power equipment — it is very dangerous.
- Leave it to technicians who are experienced and also understand the risks involved.
Don't Touch The Shiny Bits & Trust No One
If you have any questions at all, please call us. We will be happy to help you with any power related problem or query. Advice is always freely given — it costs nothing to ask a question.
Glossary
Tough black rubber base with non slip yellow polypropylene top section. Can be used with cables or pipe work. 3 channels each approx 3 x3 inch.
Very strong and durable. Use where public or traffic crosses cables or where any cables cause problems with access.
Camloc is a neoprene rubber covered copper insert type single pole in line and panel mount connector system very common in Rock n Roll / temporary power distribution. Comprises male & female mating parts, locks with 90 degree turn (check for nipple inside female part, no nipple no lock). Cable which should have copper shim wrapped round it to give better connection is held in place inside insert by two alllen screws, cable sheath should be held by twisted wire wrapped round cable & then stuffed into insert before tightening allen screws.
Fairly heavy duty around 300A @ 250V AC. Possibly no IP rating and it fails standard British finger test. Not ideal but does the job well, no decent sensible replacement as yet. Safe when used by experienced personnel, who are aware of risks. For maximum safety should not be handled/connected when live.
The POWERLOCK is very similar to the Camloc with the exception of being considerably SAFER. All live parts are insulated from touch.
Ceeform are also know as MK Commando connectors to BS4343. Circular plastic connectors favoured in the temporary power distribution business. Colour coded for easy identification and safety. Most common in europe are red = 415V, blue = 230V, yellow = 110V. Also available in grey and purple. US types have different colour coding (blue = 208V).
Standard sizes are as follows. All sizes are available in 1-phase or 3-phase.
- 125A
- 63A
- 32A
- 16A
1-phase modular system distro
3-phase modular distro
American domestic three pin plugs & sockets rated @15A 125V AC. Can be higher rated, best quality marked "hospital grade".
REMEMBER: U.S. LIVE is on the left hand side - our LIVE in UK is on the right hand side of the socket.
Their connectors can sometimes also be colour coded:
- GOLD = Live
- SILVER = Neutral
- GREEN = Earth
US cable colour coding is normally as follows.
- SINGLE PHASE
- BLACK = Live
- WHITE = Neutral
- GREEN = Earth
- THREE PHASE
- BLACK, RED & BLUE = Lives
- WHITE = Neutral
- GREEN = Earth
Electronic Line Voltage Conditioner again consists of an isolation transformer c/w triac regulated control on the output which switches in and out different tapps on the transformer as current passes through zero point of cycle. Input range -20% +10% from nominal 220V or 240V. Output stable 5%. Lighter and much quieter than passive version. Operates on 50 or 60 Hz.
Rotary
The incoming AC powers an electric motor which through a mechanical or toothed belt link drives an AC alternator to generate a different frequency and or voltage from the input. Can be a bit noisy but ok for some applications,except for.Monobloc construction, single shaft type very quiet and high quality, designed to run computers and other sensitive equipment.
Static
This device converts the incoming power to DC then through a software or crystal analog controlled Inverter, changes it back to AC at a different frequency from the input. Similar internal technology to some UPS systems but without the battery back up facility.
Inverters turn DC into regulated AC. Various types are available - ours have a sine wave output. Square or semi-sine are more common and will work just fine for fridges etc but may damage sensitive electronics, so check your application for this before hire/buy. In some UPS systems, the DC to AC section can be used as an Inverter.
A load bank is a device which enables you to put a controlled linear (resistive) loading onto equipment under test in order to prove the equipment will support the load under real conditions and also to prove all systems are correctly calibrated for overload and other parameters.
UPS and generators are systems which are tested on load banks. Available in two types most common are Resistive or some applications require Reactive. Resistive banks are usually made from precision heater elements and have a power factor of 1. Reactive banks have additional capacitors and coils which can be introduced to provide high crest factor.
Line Voltage Conditioner (also know as a power conditioner) consists of a self regulating isolation transformer c/w tuning capacitors on output winding. Units provide high quality sine wave output even from distorted input waveforms. LVC does a similar job to UPS but without battery back up. Input range -20% +10% from nominal 220 or 240V. Output stable >5%.
It can fill in micro interruptions to the supply up to 1 cycle or 20 milliseconds. Has very good off load to full load regulation, very fast correction to output voltage. Only operates on fixed frequency specified at purchase date; all of ours are 50Hz but 60 Hz are available. Heavier and acoustically noisier than electronic versions (see above).
Associated and sometimes confused with the ELCB or earth leakage circuit breaker.
Before we explain what a RCD is and how it works please remember SAFETY FIRST, if you don't know then DON'T TOUCH always ask for help from a qualified engineer.
Both devices disconnect the supply to the load in the event of a fault being detected which causes current to flow where it should not be flowing.
For example if equipment has an input short circuit between say NEUTRAL & EARTH then the return current from the circuit will appear on both the NEUTRAL & EARTH conductors when of course it should only appear on the NEUTRAL not on the EARTH.
When this situation occurs the protection device opens the circuit and protects the USER --- Thats you--- from electric shock or worse!!!!!. How it works is relative simple (diagram soon) words first.
Current flows through the load and the mathematical vector sum of this flow in a normal system is ZERO now I don't know why, but is is ZERO. This holds true for both single & three phase systems.
The conductors LIVE & NEUTRAL of the circuit pass through a current transformer or CT. The conductors form the primary of this circuit and the CT through which they pass is the secondary.
O.K. so a fault current (that is a deviation from ZERO) flowing in the primary winding will induce a current in the secondary, this current is detected by the RCD and operates a relay to trip the circuit.
If you use one DEMAND A TEST CERTIFICATE from a QUALIFIED ENGINEER. If it does not have a test certificate! use it AT YOUR RISK!.
News From Our Design Team
Backroom's RCD control module utilises FDB equipment control technology and removes the traditional problems associated with multi level sensitivity RCD relays interfaced with heavy duty mccb's commonly used in the hire industry.
As you may be aware many users have in the past had access to all system parameters. After time the legends can rub off and the presets interface becomes damaged & ineffective. At this stage even the experienced qualified tech has difficulty in setting the system correctly!.Any other staff who may wish to change the thresholds can become completely confused and errors occur. Instead of changing the tripping threshold they may inadvertently mulitply the time delay!.
The main problem of user tampering is completely removed all control parameters normally available to the user have been installed behind perspex panel secured with tamper proof screws.
Setting the system is simple. The user presses the program button and dials the setting required on the thumbwheel, settings are indicated in the table adjacent to the thumbwheel. Once the setting has been selected there are no ambiguous parameters, the settings are all contained in the relay selected. Setting can be changed at any time.
RCD module status is confirmed by LED indicators: Power on, RCD in, RCD trip. Relays are available in any suitable configuration of threshold and time delay requested by the customer at ordering date.
Up to 9 different settings are available, however, 6 is the norm for most applications to date. All RCDs we supply ship with a current valid test certificate & instructions.
400A RCD
Transformers with only one winding, therefore the neutral point is common to both input and output. Does not isolate the load from the supply.
Transformers with two separate windings - no connection from primary to secondary windings. Can be used to create separate supply for sensitive or critical electronics. The most common type in use is the encapsulated type, usually yellow in colour providing 110V CTE. This configuration results in a supply of 55V-0-55V where 0 is common with ground. By limiting the voltage available between any 1 conductor and earth, this design limits the possibility of a fatal electric shock. Isolation transformers are mandatory on some construction sites.
Uninterruptible Power Supply supplies the critical load with clean conditioned power and in the event of mains failure or other mains fault switches to internal battery power continuing supply until controlled shutdown is effected or supply returns to normal. Input range -10% +10% from nominal 110,220 or 240 /50 or 60 Hz. All our units are on line sine wave output. Ferro-resonant UPS based upon LVC transformer design are generally not frequency tolerant.
UPS systems are available in different formats:
- Single phase in/out, 230V in and 230V out.
- Three phase in /single phase out, 400V in and 230V out.
- Three phase in/out, 400V in and 400V out.
Variac is a contiuously variable auto transformer available in single or three phase. With a variac you can start at any voltage, including 0 Volts, and gradually increase the supply voltage to equipment under test, until it reaches the test point or maximum required. Very useful for repairing power supplies or providing non standard voltages for a variety of equipment. Most test labs will have at least one. One point to note: the wiper connection should always be fused because, if the variac is misused, it will very quickly burn out the windings.
The large variacs are oil immersed - they are very heavy!
