Brakes

Dunkermotoren E300A Power-On Brake

Name: E300A Dunkermotoren E300A Power-On Brake
SKU: E300A

The Dunkermotoren E300A is a 24 Vdc power-on brake rated at 2.5 Nm nominal torque, with a torque range of 1.50–3.50 Nm over the temperature range. A power-on brake applies torque when it is energised and releases when supply is removed: the opposite of the power-off brakes in the Dunkermotoren range. It is specified where braking is a commanded ...

The E300A draws 0.41 A at 10 W nominal input power, engaging in 17 ms and releasing in 8 ms. This is quicker to release than the smaller E50A and E105A despite applying more torque, which matters where an axis has to be freed between cycles. It measures 65 mm in diameter by 40 mm long, weighs 0.35 kg, runs with low noise and carries IP 20 protection as supplied. Connection is by 400 mm Teflon leads of 0.5 mm² cross-section, black for GND and red for Vdc.

Power-on brakes are supplied on request. All rated values apply in the run-in condition.

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Dunkermotoren E300A electromagnetic holding brake with metallic housing, central bore and mounting pins

Features

Power-on operation applies braking torque only when energised: the axis runs free when the machine is unpowered, for commanded rather than fail-safe braking
2.5 Nm nominal braking (1.50–3.50 Nm over temperature), stepping up the power-on range for heavier commanded axes
Engages in 17 ms and releases in 8 ms for quick commanded braking, quicker to free the axis than the smaller E50A and E105A
Low-noise operation for quiet installations
IP 20 as supplied, or up to IP 65 with covers
400 mm Teflon-insulated leads, 0.5 mm² (black GND, red Vdc) for direct wiring

Specifications

POWER-ON BRAKE SPECIFICATIONS
Nominal voltage	Vdc	24
Nominal torque⁽¹⁾	Nm	2.5
Torque range⁽¹⁾⁽²⁾	Nm	1.50–3.50
Nominal current⁽¹⁾	A	0.41
Nominal input power⁽¹⁾	W	10
Activation time	ms	17
Deactivation time	ms	8
Protection class	IP	20
Weight	kg	0.35
Noise	–	low noise
Diameter (Ø)	mm	65
Length (L)	mm	40
Strand colour GND	–	black
Strand colour Vdc	–	red
Strand length	mm	400
Strand type / cross section	–	Teflon 0.5 mm²
(1) Values valid in run-in condition
(2) Over the temperature

Downloads

dunkermotoren-e-300-a-24vdc-power-on-brake-datasheet.pdf

Warranty & Returns

Warranty periods vary by product. Please refer to the Powerbox Warranty Policy for the applicable coverage period against manufacturing defects from date of purchase. For returns and RMA requests, please visit our RMA support page or contact our support team directly.

FAQs

What torque does the Dunkermotoren E300A apply, and where does it sit in the range?

The E300A applies 2.5 Nm nominal torque with a 1.50–3.50 Nm range over temperature on a 24 Vdc supply, second from the top of the power-on series: E46A at 0.3 Nm, E50A at 0.4 Nm, E105A at 1.7 Nm, E300A at 2.5 Nm and E605A at 4.5 Nm.

What is the difference between a power-on brake and a power-off brake?

A power-on brake applies torque when it is energised and releases when supply is removed. A power-off brake does the reverse: it holds when de-energised, so the axis is caught automatically on power loss or emergency stop. Choose a power-on brake such as the E50A, E105A or E300A where braking is a commanded step in the cycle; choose a power-off brake from the E22R to E600R range where the load must not drift while the machine is unpowered. A power-on brake is not a fail-safe holding brake and should not be specified as one.

Why does the E300A release faster than the smaller power-on brakes?

The E300A deactivates in 8 ms, against 15 ms for the 0.4 Nm E50A and 40 ms for the 1.7 Nm E105A, so it frees the axis more quickly despite applying more torque. Activation is 17 ms. Where cycle time is limited by how fast the brake lets go rather than how fast it grips, that trade favours the E300A over the E105A.

What are the full electrical ratings of the E300A?

It runs on 24 Vdc drawing 0.41 A at 10 W nominal input power, engages in 17 ms and releases in 8 ms. All rated values apply in the run-in condition, and the torque range applies over the temperature range.

What are the dimensions and connection details of the E300A?

The E300A measures 65 mm in diameter by 40 mm long and weighs 0.35 kg. It is supplied with 400 mm Teflon leads of 0.5 mm² cross-section, black for GND and red for Vdc: the only Teflon-insulated leads among the brakes for which Dunkermotoren specifies strand type in the datasheet.

What IP rating does the E300A have?

The brake itself is IP 20 as supplied. Brakes can be mounted to the motor openly or with covers in protection class up to IP 65, and in combination with brushless motors they can be integrated into the motor profile housing at IP 65. The achievable rating therefore depends on the mounting arrangement rather than on the brake alone. Dunkermotoren does not publish a BG motor pairing for the E300A. If an IP 65 integration is required, the E105A is the power-on brake with defined BG65 and BG75 pairings.

Are the power-on brakes stock items?

Dunkermotoren supplies the full power-on series (E46A, E50A, E105A, E300A and E605A) on request rather than as standard catalogue items, so lead times differ from the power-off range. Contact sales@powerbox.com.au for current availability before designing one in.

How do I select the right brake for my Dunkermotoren motor?

Selection depends on the torque required at the axis, whether the brake must hold on power loss or only when commanded, the motor series it mounts to, and whether an IP 65 profile-housing installation is needed. Send your motor model and duty details to sales@powerbox.com.au and Powerbox will confirm the right brake and mounting arrangement.

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