The EPM688-V2.5 is an Electro Permanent Magnet, combining the advantages of electro and permanent magnets. With virtually no power during steady state operation (<1mW) and 800mA for 1.2s during a switch cycle.

Holding force and consistency have been greatly improved (5kg under adverse conditions) and is more resistant to demagnetization during virbration.

The EPM688-V2.5X is an Electro Permanent Magnet, combining the advantages of electro and permanent magnets.

The magnetic domains in the Alico magnets are aligned in a particular orientation as to form a magnetic circuit with a ferrous target plate. A short, 20us pulse current of 300A is generated by discharging the main capacitor through a Thyristor full bridge into the copper winding generating a field of 70kAm. This field is used to align Alico domains.

The key advantage is a very strong electromagnet that does not consume energy during steady state operation, only during cycling.

This device comes with integrated electronics that can be operated with a 50Hz 5V PWM signal common on RC electronics. The device is designed to hold 5kg of cargo under adverse conditions with a holding force of over 80N or 8kg.

Applications

Robot work holidng
Education demonstration of magnetic properties
Cargo holdong for UAV's

Features

5-6V Vcc
PWM signal
Minimal steady state power <1mW
Water resistant conformal coating
Short cycle time
On board Pic12F with source code and in-circuit programming header

Pin Functions

GND

Ground pin

Vin

5V supply

PWM

RC PWM signal input

ICSP CLK / Data

The Data pin puts out the current state of the EPM,TTL high for On and TTL low for Off.

Vpp, Vdd, Vss, ICSP Dat, ICSP CLK

These pins are broken out to provide the user with the ability to reprogram the on board PIC12F. Further information can be found in the documentation provided by Microchip

Operation

After connection VCC and GND the device will charge the capacitor.

When an On command is given, either by toggling the push button or by a PWM signal, the device will discharge the capacitor 6 times into the coil. This takes 1750ms

When an Off command is given the device will alternately magnetize the Alnico magnets repeadly, while decreasing the amplitude of the voltage, thereby demagnetizing the Alnico magnets. This takes 1250ms.

Push Button Mode

Pressing the Push Button will toggle between an On and Off command

PWM Mode

A RC Pulse Width Modulated Signal can also be used. High times between 0.75 and 1.25ms are considered an Off command. 1.75-2.25ms are considered an On command. Moving the signal on time from neutral, 1.25-1.75ms to either On or Off range will command the EPM to go into the respected state.

Error

The Led will blink once per second if the PWM signal is not present. An error is either a. signal is missing or b.out of the time range PWM, about every 2 seconds for a missing PWM.

LED

Led goes on when the button is pressed. The Led will blink rapidly 4 times after a command has been executed, either going On or Off.