Below is a table of common faults found within the Control Techniques Unidrive series, more specifically, the UNI1405. MRO Electric offers core credit on exchanges for new and refurbished units, and have a wide selection of option cards such as the UD51, UD73, and UD77. We also repair Unidrives in-house. Contact us if you are interested in finding a new machine so we can keep your downtime to a minimum!
With the UNI1405 configuration, the volts / frequency ratio must be kept constant to ensure rated torque is available from the motor over the frequency range. At low frequencies (from 0 Hz to ½ x Pr 5.06) the voltage is increased from this characteristic by a level governed by either the voltage boost parameter or the motor parameters (found during the stator resistance test) depending on whether the drive is in fixed boost or open loop vector mode as shown aside.
UNI1405 Motor Rated Power Factor
The power factor is found by the UNI1405 4kw during the autotune procedure. It is used in the open loop vector algorithm and to set the current limit levels for the torque producing (active) current.
Emerson UNI1405 4kw Motor Rated Speed
The motor rated speed parameter should be set to the synchronous speed of the motor minus the slip speed. This is often displayed on the motor nameplate. I.e. For a typical 18.5 kW, 50 Hz, 4 pole motor the motor rated speed is 1465 rpm. The synchronous speed for a 4 pole motor is 1500 rpm therefore the slip speed is 35 rpm Synchronous speeds for different numbers of poles are as follows:
2 pole = 3,000 rpm
4 pole = 1,500 rpm
6 pole = 1,000 rpm
8 pole = 750 rpm
The accuracy of this parameter is very important as it directly affects the torque produced at the shaft. Often the value given on the motor nameplate is not
The Control Techniques UNI1405 Unidrive is a 5hp, 9.5A AC drive with a peak output of 9.6kHz. All of the Unidrives have a built-in encoder port which is ready to accept motor rotational feedback after installation. There are three option modules available to compliment or extend the range of motor speed / position feedback capabilities. For additional info about the UNI1405 manual programming of the option modules you can check out our post about the UD73 option module here.
Each of these option modules creates a simulated encoder output as either line driven quadrature channels or as frequency / direction signals to facilitate follower applications.
HF trips are internal hardware faults within the drive. Powering the drive down and re-applying power could clear the fault.
Resetting the drive will not clear a HF trip.
If a HF trip occurs, the Drive Healthy relay will open to indicate this
The serial communications will not function during a HF trip
The only HF trip that can be caused by the user is a HF82 trip where a
large option module is removed while the drive is powered up.The drive should be powered down, the module re-fitted correctly and the power reapplied to clear the trip