Safety Instructions
The Purchaser/user is to comply with the instructions and information given here and ensure that all personnel to be associated with the apparatus supplied are made familiar with this information.
The apparatus supplied could, when energised, constitute a safety hazard and must be correctly installed in a suitable location by technically qualified and competent persons.
Hazards
The equipment may operate at dangerous voltages and produce high temperatures when in operation. The unit is fitted with labels to warn of these hazards.
Installation
The braking resistor must be mounted on a flat surface ideally in a horizontal position. If the unit is to be mounted vertically then the cable compartment must be mounted lower most, (as shown below) to avoid heating the cables during operation.
Correct installation:
- Solid plate at the base
- Termination compartment at side or base of unit
Incorrect installation:
- Solid plate at the top preventing adequate cooling
- Termination compartment at top of unit in hot air stream
- Resistors stacked on top of each other
A free-air flow environment is required around the resistor enclosure. The minimum recommended clearance to other equipment is 250mm. Particular attention should be paid to the clearance above the unit, as the exit air above the unit may be dangerously hot during operation.
As both the issuing air temperature and the enclosure surface temperature are likely to exceed 100庵 the ventilation holes in the enclosure must not be obstructed. In particular no combustible materials must come into contact with or be in close proximity to the top cover or the sides of the enclosure.
Two or three tier enclosures can only be mounted in a horizontal position. Where canopies are fitted these must be fitted uppermost.
On drives <=7.5kW an internal brake resistor may be fitted, this Must Be Disconnected when external brake resistors are used.
Installation Procedure
- Identify suitable mounting surface in accordance with the requirements given.
- Remove top cover giving access to mounting holes in base plate.
- Secure unit to mounting surface using suitable fastenings.
Wiring
One Dynamic Braking Resistor (DBR) unit may be supplied as single or multiple enclosures, resistors in multiple enclosures should be connected in parallel
All enclosures are fitted with over temperature sensors, which should be connected to the EMS input on the inverter, sensors in multiple enclosures should be connected in series.
Cable access can be facilitated via cable knock-outs (single-tier units) or un-drilled gland plate (two or three tier units).
Notes
- Resistor is not polarity sensitive.
- Before operation ensure all electrical connections (including earth) are tight.
- Ensure that the top ventilation cover is free from obstruction.
- If multiple enclosures are used, ensure correct connection by verifying the final resistance value is within 臼0% of the required value.
- If resistors are mounted within an enclosure measures must be taken (fans / cooling) to dispose of the heat generated.
Maintenance
The equipment must be completely isolated from any power supply before any maintenance is carried out. Very little maintenance is required on this equipment, but maintenance inspections should be carried out at regular periods to ensure that the equipment is kept in a good and reliable condition. During maintenance inspections check that all connections are tight and the ventilation covers of the enclosure are free from any obstruction and as dirt-free as possible, and the danger labels on the exterior of the enclosure are kept in position and clean.
Return to Questions |
