Cressall

Dynamic Braking

Standard dynamic braking resistors on demand

Cressall’s standard ranges of high capacity dynamic braking resistors (DBRs) for regenerative and rheostatic electric motor braking are low cost, easy to specify, quick to install and with ratings to suit inverter drives of any power. Our wide range of resistor technologies means that we can select the most technically appropriate and cost-effective resistor design for any application, whether continuous, intermittent or infrequent.

We offer two product ranges to cover continuous powers up to 100kW:
ES and DBR ranges for powers to 25kW
SD and HPR ranges for powers to 100kW

Dynamic Braking Resistors

A Cressall dynamic braking resistor installed on top of a drive control cabinet

Benefts of using Cressall Dynamic Braking Resistors

  • Low cost: Achieved through better design, standardisation and use of common components
  • Easy to specify: Standard enclosure designs for powers to 100kW
  • Standard power ratings: Continuous ratings from 600W to 100kW continuous

Fast delivery: For same day dispatch of stock items (ES and DBR) in the UK contact our UK distributor: CP Automation before 10.00am. Units not held in stock can be manufactured quickly.

Performance: Our range of elements combine excellent heat dissipation for continuous braking with the highest active surface area per kW in the industry, giving outstanding short-time performance for repetitive braking duties.

Confidence: Our experience in supplying resistors for electric motor brakes combined with accurate sizing software means we can predict the performance of your resistor for any specified duty cycle.

ES and Braking Resistor Designs to 25kW

Cressall ES and DBR braking resistors are based on two types of resistor elements:
HP Coils: spiral wire-wound coils on ceramic formers
ZC Coils: edge-wound coiled strip on ceramic formers

Both elements offer high overload capacity and rapid cooling. The alloys used have low changes in resistance over the temperature range: no more than 18%, unlike designs using 304 stainless steel which can increase in resistance during the heating cycle by as much as 50%, resulting in lower braking currents and less effective braking.


ES Series, 0.6 – 8kW Continuous

  • Our ES range is usually available from stock so there’s no waiting for the right DBR
  • Spiral wire wound resistor element on ceramic former
  • Negligible noise
  • Low inductance
  • Temperature stable design, low increase of resistance value
  • Optional thermal switch
  • Terminal block mounted at one end of the enclosure, cover for terminal block, allow for ingress protection IP 20
  • Easy installation: Pre-drilled mounting holes, knock-outs in terminal cover, units suitable for horizontal or side mounting.

DBR Series, 6 -25 kW Continuous:

  • Spiral wire or wound edgewound strip resistor element
  • Temperature stable design, low increase of resistance value
  • Standard thermal switch
  • Option for IP21 drip proof canopies
  • Integral terminal compartment
  • Easy installation: Pre-drilled mounting holes, knock-outs in terminal compartment, units suitable for horizontal or side mounting.
  • Option for 304 stainless steel enclosures
  • Dispatched from stock for common sizes, manufactured in a few days for other ratings.
Standard dynamic braking resistors

Cressall’s standard dynamic braking resistors are available in the most common application ratings from stock. They are suitable for all kinds of drives, any power or duty cycle and offer easy installation and low running costs.

Power
kW
DBR Resistance
Min. Value
Resistance
Tolerance
Dimensions, mm
L W H
Mounting centres
L W
Weight
kg
0.6kW ESH 4.7Ω -0/+5% 288 121 141 236 92 1.4
1kW EST 6.8Ω -0/+5% 367 121 141 315 92 1.8
1.5kW ES1 10.0Ω -0/+5% 467 121 141 415 92 2.2
2kW EST2 3.3Ω -0/+5% 367 213 141 315 185 3
3kW ES2 5.0Ω -0/+5% 467 213 141 415 185 3.8
4.5kW ES3 3.3Ω -0/+5% 467 307 141 415 278 5.4
6kW ES4 1.5Ω -0/+5% 500 388 195 410 360 6.6
8kW ES8 0.75Ω -0/+5% 500 388 390 410 360 11.5
1.5kW HP1 10.0Ω -0/+10% 508 144 140 451 86 4.5
3kW HP2 5.0Ω -0/+10% 508 239 140 451 181 6.5
4.5kW HP3 3.3Ω -0/+10% 508 333 140 451 275 8.5
6kW DBR12 2.7Ω -0/+10% 766 330 140 700 290 16
9kW DBR18 2.7Ω -0/+10% 800 335 304 700 290 25
12kW DBR24 2.7Ω -0/+10% 800 335 304 700 290 33
18kW DBR36 1.5Ω -0/+10% 800 335 429 697 280 45
25kW DBR54 1.5Ω -0/+10% 800 539 453 697 480 60

SD and HPR series braking resistors – to 100kW

For higher power applications Cressall offer expanded mesh and stamped grid resistor designs, well proven in regenerative and rheostatic braking applications around the world. With these elements we can offer flexible and cost effective solutions for higher powers and heavy overloads. Units are designed to meet the customer’s specified duty but are based on standard formats, meaning that design, manufacture and despatch can be in just a few weeks.

  • Low inductance expanded mesh or stamped grid element
  • Choice of resistance alloys giving a wide cost vs. performance option
  • Choice of enclosure materials: pre-galvanised mild steel, 304 or 316 stainless steel allowing designs to be optimized for both price and performance.
  • Optional thermal switch Option for IP23 drip proof canopies
  • Manufactured to order but dispatched in a few weeks to standard designs