Yes, the single MegAlert units can be equipped with a push button test feature to eliminate the auto mode or the multiple units can simply be left in the manual position.
Can you use a MegAlert on motors powered by a variable frequency drive or solid state soft start?
Yes, providing that an isolation contactor is installed to isolate the motor from the VFD of soft start. If there is no contactor in the system one can be provided with the MegAlert system. The older type auto transformer soft starters do not affect the MegAlert.
Will damage occur to the MegAlert if the "motor run" control signal fails and the MegAlert stays in the circuit with the operating voltage present?
No, the MegAlert high internal impedance protects the system and allows the test voltage to trip out the MegAlert on an alarm after the service ground is detected.
How are maintenance personnel made aware that the equipment is being automatically tested by the MegAlert?
Remote flashing LED assemblies can be mounted on the door of the control cabinet or motor starter bucket and warning labels are provided with the MegAlert to be mounted on the equipment as well as the switchgear doors.
How far can a motor or generator be from the MegAlert unit?
The MegAlert can be up to 1,000 ft. from the equipment being tested as long as the test lead is wired with a minimum of 18 AWG wire.
On a 4160 volt system, how are maintenance personnel protected from high voltages at or coming from the MegAlert unit?
The GP2500 and GP5000 MegAlert systems are fused and current limit protected, both on the output from the MegAlert and from the motor operating voltages, for personnel safety. Remote and local "power on" LEDs are provided with the MegAlert systems as well as a latching power on/off switch to indicate and remove power from the MegAlert system. The MegAlert when wired correctly is powered down during normal lock and tag out of the power disconnect switch.
Will the MegAlert harm any of the solid state control equipment (voltage regulator, metering, etc.) in my generator control panel?
No, the MegAlert tests between the phases and ground. Thus, there is no potential for high test voltages on control equipment, unless they are connected between a phase and ground. On 240 VAC generating systems, it may be necessary to install isolating transformers to protect control equipment.
Is there any deterioration of the insulation by continuously testing at a rated voltage?
No, the unit will not cause an insulation breakdown because it uses a nondestructive D.C. test voltage with current limiting to a maximum of 350 micro amps. Our patented voltage/current safely circuitry also protects dead grounded equipment from being harmed.
Can you set different alarm settings or test voltages on each motor or generator on the multiple models MegAlert?
No, one common alarm setting and testing voltage is used for all test points on the multiple model MegAlert.
Can the MegAlert be used on motors or generators with low current in- winding heaters?
Yes, in some cases it may be necessary to install an isolation transformer or contactor on the heater input voltage circuit.
Can you set multiple set points (trip points) with one unit?
Yes, some models are available with two set points: a pre-alarm and alarm. The first trip point is a pre-alarm to indicate early insulation breakdown. The second trip point is an alarm that indicates that corrective measures should be taken to prevent an impending failure.
My motors run 24 hours a day. How can MegAlert benefit me?
Most equipment that operates 24 hours a day is critical and can not afford lengthy downtime, however preventative maintenance testing is required. The MegAlert allows you to perform your PM test with the minimal amount of downtime and expense and can be done quickly during any normal interruption that may occur with that type of equipment. Manual testing would not be possible in this situation.
Can you automatically test the insulation resistance on grounded generator Systems?
Yes, by installing our ground interrupter on each grounded generator equipped with a MegAlert, to remove all grounds before automatically testing the insulation resistance. A safety circuit is provided to ensure that the ground is re-connected before the generator can produce voltage.
Can you automatically test the insulation resistance for submersible pumps?
Yes, the MegAlert will check submersible pumps and the underwater cables from the starter to the motor.
Where is the MegAlert normally located in a typical circuit?
The MegAlert in connected to one of the phases, at the motor contactor or generator breaker and to the equipment ground, and is generally mounted in or next to the motor control center or generator switchgear. The medium voltage models need to have the MegAlert located in the H.V. compartment of the control cabinet or in a separate enclosure.
Can I use more than one test voltage per MegAlert?
No, the MegAlert can only provide one test voltage value per unit.
We have lightning arrestors and power factor correction capacitors in our motor control centers. Can we still use the MegAlert?
Yes, providing that there are no direct grounds on the motor side of these components. A time delay is built into the MegAlert systems to allow for some charging effects in such cases. Good lightning arrestors and power factor capacitors do not affect the MegAlert readings.
Can you use the MegAlert on motors when they are running?
No, The MegAlert is designed to test equipment that is not in operation and prevent an insulation failure on start up.
Can you use the MegAlert on synchronous motors?
Yes, the brushless type synchronous motors will only require (1) MegAlert. The brush type synchronous motors can use (2) MegAlert, one on the stator and one on the rotor.
Can you use the MegAlert on A.C. and D.C. motors?
Yes, the MegAlert is designed to test both A.C. and D.C. equipment.
Will surge capacitors on a motor affect the MegAlert?
Most surge capacitors have bleed resistors connected to ground that affect the MegAlert readings. The capacitors have to be replaced with the type that does not have bleed resistors in order for the MegAlert reading to be correct. (GE makes a capacitor with no bleed resistors).
